Windows is unable to run Automatic Maintenance

PC Performer is a registry cleaner made by PerformerSoft. The purpose of this program is to remove redundant items from the Windows registry. Registry cleaners remove broken links, missing references within the Windows registry. PC performer is designed to automatically optimize your registry and clean it up.

PC Performer adds registry entries for the current user that allow it to run automatically each time the system is rebooted. It adds a scheduled task to Windows Task Scheduler in order to run at various times. The software connects to the internet, therefore it creates a Windows Firewall exception that allows it to connect without interference. Multiple anti-virus programs detected this software as Malware, it typically comes bundled with other software or is distributed through a pay-per-install bundle.

About Potentially Unwanted Applications

People have encountered it – you download and install a piece of free software application, you then see some unwanted applications on your computer or discover a strange toolbar has been added to your browser. You didn’t install them, so how did they turn up? These unwanted programs, technically known as Potentially Unwanted Programs (PUPs), often come bundled along with other software and install themselves on user’s PC without their knowledge. They perhaps might not look like viruses to some individuals, but they can produce major annoyances and bring about serious trouble for users. The idea of PUP was coined to define this downloadable crapware as something other than malicious software. Much like malware, PUPs create problems when downloaded and placed on your computer, but what makes a PUP different is that you provide consent to download it – the fact is vastly different – the software installation bundle actually tricks you into agreeing to the installation. Still, there isn’t any doubt that PUPs are still bad news for computer users as they can be incredibly damaging to your computer in lots of ways.

What do PUPs look like?

The unwanted software programs after installation display loads of annoying pop-up adverts, create fake alerts, and quite often it even pushes the user to buy the software. Likewise, the majority of free software applications these days come with quite a few unwanted add-ons; in most cases a web browser toolbar or browser modification such as a homepage hijacker. Not only they needlessly use up space on your screen, but toolbars can also manipulate search engine results, watch your browsing activities, decrease your web browser’s performance, and decelerate your net connection to a crawl. PUPs employ aggressive distribution techniques to get in your computer. Some might include information gathering program code that could collect and send your private information back to third parties. Due to this unwanted program, your application may freeze, your security protections may get disabled that might leave the computer susceptible, your system may get ruined, and the list goes on and on.

Tips on how to prevent ‘crapware’

• Read cautiously before agreeing to the license agreement as it may have a clause about PUPs. • Usually, when setting up a program you will get two options, ‘Standard Installation (recommended)’ and ‘Custom Installation’. Don’t select ‘Standard’ as PUPs could be installed that way! • Use good anti-malware software. Try Safebytes Anti-Malware which will find PUPs and handle them as malware by flagging them for removal. • Be alert when you install freeware, open-source software, or shareware. Avoid downloading browser extensions and programs you are not familiar with. • Only download applications from the original providers’ sites. Avoid download portals as they use their own download manager to pack additional programs with the initial download.

What you can do if Virus Stops You From Downloading Or Installing Anything?

Malware could potentially cause several kinds of damage to computer systems, networks, and data. Certain malware goes to great lengths to stop you from installing anything on your PC, especially antivirus applications. If you’re reading this right now, you have perhaps recognized that a malware infection is a reason for your blocked web traffic. So what to do if you need to install an antivirus program like Safebytes? There are a few actions you can take to get around this problem.

Eliminate malware in Safe Mode

If the virus is set to load automatically when Microsoft Windows starts, getting into Safe Mode could very well block the attempt. Since just the bare minimum programs and services start-up in safe mode, there are hardly any reasons for issues to happen. The following are the steps you should follow to remove malware in Safemode. 1) At power on/start-up, hit the F8 key in 1-second intervals. This will bring up the Advanced Boot Options menu. 2) Select Safe Mode with Networking using arrow keys and hit ENTER. 3) Once you get into this mode, you should have an internet connection again. Now, obtain the malware removal application you need by using the browser. To install the software, follow the directions in the installation wizard. 4) After installation, do a complete scan and let the software delete the threats it detects.

Switch to an alternate browser

Web-based viruses can be environment-specific, targeting a particular web browser or attacking particular versions of the browser. The best solution to overcome this issue is to opt for a browser that is well known for its security features. Firefox contains built-in Phishing and Malware Protection to keep you safe online.

Install and run anti-virus from a USB drive

To successfully eliminate the malware, you will need to approach the issue of installing an anti-virus program on the infected PC from a different angle. Adopt these measures to employ a USB flash drive to fix your corrupted computer. 1) Use another virus-free computer to download Safebytes Anti-Malware. 2) Insert the pen drive into the clean computer. 3) Double-click the Setup icon of the antivirus program to run the Installation Wizard. 4) When asked, choose the location of the pen drive as the place where you would like to put the software files. Follow the on-screen instructions to complete the installation process. 5) Now, insert the pen drive into the infected computer. 6) Double-click the EXE file to open the Safebytes program right from the flash drive. 7) Click “Scan Now” to run a scan on the infected computer for malware.

Highlights of SafeBytes Anti-Malware

Do you want to install the best anti-malware software program for your computer system? There are various applications in the market that comes in paid and free versions for Microsoft Windows systems. A few of them are great and some are scamware applications that pretend as legit anti-malware software waiting around to wreak havoc on your computer. While looking for anti-malware software, select one which gives dependable, efficient, and full protection against all known computer viruses and malware. On the list of recommended software is SafeBytes Anti-Malware. SafeBytes carries a really good track record of top-quality service, and clients are happy with it. SafeBytes anti-malware is a highly effective and easy-to-use protection tool that is suitable for users of all levels of computer literacy. With its cutting-edge technology, this application will let you remove multiples types of malware which include viruses, worms, PUPs, trojans, ransomware, adware, and browser hijackers. SafeBytes anti-malware provides an array of advanced features which sets it apart from all others. Listed here are a few of the great ones: Anti-Malware Protection: Built on a highly acclaimed anti-virus engine, this malware removal tool is able to detect and remove many obstinate malware threats such as browser hijackers, potentially unwanted programs, and ransomware that other typical anti-virus programs will miss. Real-time Active Protection: SafeBytes offers an entirely hands-free real-time protection that is set to check, prevent and remove all threats at its first encounter. It’ll check your PC for suspicious activity continuously and shields your PC from unauthorized access. Faster Scan: SafeBytes’s virus scan engine is one of the quickest and most efficient in the industry. Its targeted scanning seriously increases the catch rate for malware that is embedded in various computer files. Safe Browsing: Safebytes assigns all sites a unique safety ranking that helps you to have an idea of whether the webpage you’re going to visit is safe to view or known to be a phishing site. Low CPU Usage: SafeBytes is renowned for its minimal influence on processing power and great detection rate of countless threats. It runs silently and efficiently in the background so you’re free to use your computer at full power all the time. 24/7 Customer Support: SafeBytes provides 24/7 technical support, automatic maintenance, and software upgrades for the best user experience.

Technical Details and Manual Removal (Advanced Users)

If you wish to manually remove PCPerformer without the use of an automated tool, it may be possible to do so by removing the program from the Windows Add/Remove Programs menu, or in cases of browser extensions, going to the browsers AddOn/Extension manager and removing it. You will likely also want to reset your browser. To ensure the complete removal, manually check your hard drive and registry for all of the following and remove or reset the values accordingly. Please note that this is for advanced users only and may be difficult, with incorrect file removal causing additional PC errors. In addition, some malware is capable of replicating or preventing deletion. Doing this in Safe Mode is advised.

The following files, folders, and registry entries are created or modified by PCPerformer

So, what is Electron bot, and why it even matters if it is in the MS store. Electron bot is malware that somehow found its way inside MS Store via game clones of popular games temple run and subway surfer. This infiltration led to the infection of around 5000 systems over the globe in a very short period of time.

This malware is a backdoor that gives complete system control to the attacker. Any type of execution can be performed remotely in real-time. Usually, this kind of attack was aimed at a spread of click fraud over popular social media like Facebook, google, youtube, etc.

Primary goal

Electron Bot's primary goals in the ongoing campaign analyzed by researchers are:

• SEO poisoning – Create malware-dropping sites that rank high on Google Search results.
• Ad clicking – Connect to remote sites in the background and click on non-viewable advertisements.
• Social media account promotion – Direct traffic to specific content on social media platforms.
• Online product promotion – Increase store rating by clicking on its advertisements.

These functions are offered as services to those who want to increase their online profits illegitimately, so the gains for the malware operators are indirect.

Publishers that contain malware

For now, users may take note of the publishers who released confirmed malicious game apps using the following names:

• Lupy games
• Crazy 4 games
• Jeuxjeuxkeux games
• Akshi games
• Goo Games
• Bizzon Case

Missing MSVCR80.dll Error - What is it?

Msvcr80.dll is a runtime dynamic link library file. This file is typically required to run programs written with Visual Studio. Msvcr80.dll error messages might appear when using or installing certain programs on your PC, that are dependent on the Msvcr80.dll file to run and load. This error message may appear on your computer screen in either of the following formats:

• "Msvcr80.dll Not Found"
• "This application failed to start because msvcr80.dll was not found. Re-installing the application may fix this problem."
• "The file msvcr80.dll is missing."
• "Cannot start [APPLICATION]. A required component is missing: msvcr80.dll. Please install [APPLICATION] again.
• "APSDaemon.exe - System Error - MSVCR80.dll is missing from your computer."
• "Cannot find [PATH]msvcr80.dll"

Solution

Error Causes

Msvcr80.dll error is a common Windows PC error. This error code may occur due to multiple reasons. These include:

• Removal and corruption of Msvcr80.dll file
• Registry issues
• Viral infection
• Hardware failure
• Improper software installation

It is advisable to resolve this error code to avoid inconvenience. This error may hamper your ability to access and run your desired program.

Further Information and Manual Repair

Here are some of the best and easiest DIY solutions to fix the Msvcr80.dll error on your PC right away:

1. Check your Recycle Bin for the Missing Msvcr80.dll file or Download the Msvcr80.dll file from a Trusted Website

If you receive the error message ‘missing Msvcr80.dll file’ then first check the recycle bin. It is possible that you may have unknowingly deleted the Msvcr80.dll file while uninstalling a program from the PC. Remember dll files are shared files. These files are used by a number of programs on your PC to run and load. There is a possibility that the program you uninstalled shared the same file to run on your PC. So, when removing that program from your PC it could have also deleted the Msvcr80.dll file. Therefore, check your recycle bin to restore the missing file. Nonetheless, if in case you are unable to locate the missing Msvcr80.dll file, then try downloading it on your PC. However, when doing so, make sure you download the file from a reliable dll download website.

2. Uninstall and Reinstall Apple iTunes Program

This error commonly pops up when running Apple iTunes on your PC. To resolve this issue, and ensure smooth access to Apple iTunes, here’s what you need to do: uninstall from Windows the following programs in this order: Apple iTunes, Software update, Apple Mobile device support, Bonjour, application support, iCloud and mobile me. Skip over software that you haven’t installed already on your system. When uninstalling the programs, if you have two entries of the same software, then uninstall the older version first and then the newer one. To do so, go to Applet in the Control Panel.  It is called programs and features in Windows 7, 8, and Vista and add/remove programs in Windows XP. Once all Apple software is uninstalled, the next step is to download the latest version of iTunes from Apple. After the software is downloaded on your system successfully, run it. This is most likely to resolve the issue.

3. Scan for Viruses

If the issue still persists, then the underlying cause could be related to malware invasion. Therefore in such circumstances, it is advisable to scan for viruses and malware with a powerful antivirus on your PC and remove them right away. Please note, using an antivirus may slow down your PC performance.

4. Perform Registry Scan and Repair

When the registry is overloaded with unnecessary and redundant files like junk files, cookies, invalid entries, and bad keys, it gets corrupted easily thereby generating errors like Msvcr80.dll errors. To resolve this issue, you must perform a registry scan and repair it with a powerful registry cleaner. Whether the cause of the issue is a viral infection or the cause is related to registry problems, the best way to resolve the issue without compromising the speed of your system is to download Restoro. This is an advanced, cutting-edge, and multi-functional PC repair tool. It is compatible with all Windows versions. This software is embedded with multiple PC repair and performance-boosting utilities such as a registry cleaner, an antivirus, and a system optimizer. It has a high functional intuitive algorithm and a user-friendly interface. The registry cleaning feature detects all registry issues, wipes unnecessary files, cleans and repairs the corrupt registry and damaged dll files. The antivirus utility scans for all types of malware, viruses, Trojans, and spyware and removes them immediately. While the system optimizer module helps boost your computer’s performance to its optimal level.  In just a few simple clicks, the Msvcr80.dll error is resolved. To get started, click here to download Restoro on your PC today!

As you know, the Windows Firewall is designed not just to protect your computer from viruses and malware, and other security threats but it’s also designed to block any program from accessing the internet. Users are given the option to block both inbound and outbound traffic for any apps on their computers. However, this kind of option can often lead to not being able to access the internet. In such cases, when you try to run the Windows Firewall Troubleshooter or the Windows Network Diagnostic troubleshooter, it will throw an error message that says, “Windows Firewall is preventing connections to your computer. The Windows Firewall rule HSS DNS Leak Rule may be blocking your connection”. If you are in this kind of scenario, then you’ve come to the right place as this post will guide you on how exactly you can fix this error. When you encounter this kind of error, there are several options you can check out to fix it. You can try to allow an app or feature through the Windows Firewall or uncheck the HSS DNS leak rule in both private and public. For more details, refer to the suggestions provided below.

Option 1 – Try to allow an app or feature through Windows Firewall

The first thing you can do to get rid of the error is to allow a feature or app through the Windows Firewall. To do this, follow these steps:

• Open the Windows Defender Security Center.
• From there, select the Firewall and Network Protection option.
• Next, click on the “Allow an app through firewall” option and then click on the “Change Settings” button and make sure that you have administrative privileges.
• After that, select the app or feature you want to allow through the Firewall from the menu. You also have the option to manually add the app by using the “Add an App” option.
• Then select the between the type of network an app can access such as:
  • Private Network will allow the app to connect to the internet only at home or work.
  • Public Network will allow the app to connect to the internet from anywhere, including Public WiFi hotspots.

• Once done, restart your computer and see if it fixed the error or not.

Option 2 – Try to uncheck the HSS DNS leak rule in both private and public

The next thing you can do to fix the error is to uncheck the HSS DNS leak rule in both private and public. You can do this by following these steps:

• Open the Windows Defender Security Center.
• From there, select the Firewall and Network Protection option.
• After that, click on the “Allow an app through firewall” option and then click on the “Change Settings” button and make sure that you have administrative privileges.
• Next, scroll down until you see the HSS DNS leak rule in both private and public option and then uncheck it.
• Now restart your computer and check if the error is now gone.

There are instances when instead of fixing problems the Windows Update brings you problems on your Windows 10 computer. You might even see some pending Windows Updates which for some reason, refuse to install no matter what you do. The good thing is you won’t have to deal with those failed and pending updates that are incompletely downloaded to your PC as you can actually delete them. Follow the instructions prepared below to delete the failed and pending Windows Updates.

Step 1: The first thing you have to do is delete all the contents in the Temporary folder

• Tap the Win + R keys to open the Run dialog box.
• Next, type in “%temp%” in the field and hit Enter or click OK to open the Temporary folder.
• From there, select all the folders and files within the Temporary folder and then delete them all.

Note: %temp% is one of the many environment variables in Windows that could open the designated folder by Windows as the Temporary folder which is usually located at C:\Users[username]AppDataLocalTemp.

Step 2: Next, remove the pending.xml file

• Go to the C:\Windows WinSxS folder.
• Once you’ve opened the folder, look for a file named “pending.xml” file and right-click on it and you can either rename it or delete it.
• After that, the Windows Update should delete the pending tasks and build a fresh new update.

Step 3: Delete all the contents of the SoftwareDistribution folder

The Software Distribution folder in the Windows operating system is a folder that can be found in the Windows directory and is used to store files temporarily which might be required to install the Windows Update on your PC. Thus, it is required by the Windows Update and maintained by WUAgent. Aside from that, it also contains all the Windows Update History files and once you delete them, you will most likely lose the Update history. As a result, the next time you run the Windows Update, it may result in a longer detection time.

• Open the WinX Menu.
• From there, open Command Prompt as admin.
• Then type in the following command – don’t forget to hit Enter right after typing each one of them.

net stop wuauserv net stop bits

• After entering these commands, it will stop the Windows Update Service and the Background Intelligent Transfer Service.
• Next, got to the C:\Windows\Software\Distribution folder and get rid of all the folders and files thereby tapping the Ctrl + A keys to select them all and then click on Delete. Note that if the files are in use, you won’t be able to delete them.
• Once all the contents in the Software Distribution folder are deleted, restart your PC and then go back to Command Prompt and input the following commands again.

net start wuauserv net start bits

Since the folder has already been flushed, it will be populated afresh the instant your restart your computer and open Windows Update.

Step 4: Try resetting the catroot2 folder

You can also try resetting the catroort2 folder as it is known to fix tons of Windows Update issues. Both the Catroot and catroot2 are Windows operating system folders that are required for the Windows update process.  So when you run the Windows Update, the catroort2 folders stores the signatures of the Windows Update package and helps it in the installation. It makes use of the “%windir%System32catroot2edb.log” file in the updating process. Afterward, the updates are stored in the SoftwareDistribution folder which is used then by the Automatic Updates in order to execute the updating process. Keep in mind that you must not rename or delete the Catroot folder. Although the Catroot2 folder is recreated automatically by Windows, the Catroot folder isn’t.

Dynamic Wallpapers introduced with Mojave Update in macOS are pretty cool. Dynamic Desktop is a feature introduced in macOS Mojave (10.14), in which the desktop background changes according to the time of Mac's current location. If Location Services are turned off the Privacy pane of the System Preferences, then the time zone specified in the Date & Time preferences will be used. To apply macOS Dynamic Wallpaper on Windows 10 we need to download & use WinDynamicDesktop, a free application that lets you apply macOS Dynamic Wallpaper. After the installation, you will be asked to Configure the Schedule. While doing that you need to make sure that you enter your location correctly. You can even set specific sunrise and sunset timing by selecting “Use specific sunrise and sunset times” and changing the Sunrise and Sunset times manually. Now, you will be greeted with some of the coolest dynamic wallpapers in the market. Select a theme of your choice, click on the Download button (file size can range between 20-200 MB), and click Apply to enjoy macOS Dynamic Wallpaper on Windows 10. If for some reason you want to go back to the default Windows theme but not necessarily delete the application then right-click on the WinDynamicWallpaper icon from the taskbar, click Select Theme, select None (from the theme section) and click Apply.

Windows has tendencies to remember WIFI passwords so it can reconnect automatically to them. But from time to time we change passwords and Windows does not let us change it since he has network remembered. In this case, we will not be able to connect to the internet. In this helpful guide, we will let you know which steps you will need to take in order to solve this issue and to be able to connect to the internet again.

1. Restart Modem

   First thing first, restart your modem. Windows might see it as a new network and offer you to type in the password for it.

2. Update driver

   Sometimes the issue could be due to driver problems, open device manager and update WIFI driver or reinstall it.

3. Reset WIFI password

   Press ⊞ Windows + R type “Control” > hit Enter. Now click Network and Internet > Network and Sharing Center > Change adapter settings. Right-click on the connected Wifi and select Status. Click Wireless Properties, change the password from the Network security key section, and then click OK to reset your WiFi password.

4. Forget the network

   Click on Start > Settings > Network & Internet > Wi-Fi. Click the Manage known networks link Select the network you are looking for Select Forget.

5. Delete your WIFI profile

   Press ⊞ Windows + X to open the secret menu and click on Command prompt (admin) In command prompt windows type: netsh wlan show profile netsh wlan delete profile name=<profile name> Reboot

If you are using your Google Chrome browser and suddenly notice a constant flickering after you’ve upgraded your Windows 10 computer, read on as this post will help you sort out the issue. A lot of users have reported this screen flickering issue in Chrome after having upgraded their devices to a recent Windows 10 build. The bizarre thing about this problem is that it only affects the Google Chrome browser and when it occurs, the Chrome browser will start to flash or flicker. According to users who experience the problem in Chrome, it seems to get worse when they try to play videos on YouTube or other streaming sites. To resolve this problem, many users tried to use Chrome in Incognito Mode, cleared the browser cache as well as cookies. They even tried resetting the browser settings and reinstall Chrome but nothing seems to work. Worry not though as there are still other options you can try to fix the problem and they’re easy ones so you’ll have no problem following them. The screen flickering problem in Chrome appears to be related to the Windows background and color settings as well as incompatible display drivers. This is why it is advised that you have both the video card drivers and Chrome browser updated to prevent the same problem from happening again. To get started troubleshooting the screen flickering issue in Chrome, refer to the following options.

Option 1 – Try modifying the background and colors settings

• Tap the Win + I keys to open the Settings app.
• From Settings, go to Personalization to load the Background Preferences and if this window does not appear, just select the Background option from the left side panel.
• Next, select a Solid Color as the new background from the drop-down menu.
• After that, check if the problem is fixed. This should be fixed especially if the one that’s causing screen flickering is the Windows automatic background switching.
• Once you’ve selected the Solid color as the background preference, go to the Colors tab under Personalization. This will open a new window and from there, check the box of the “Automatically pick an accent color from my background” option.
• Now close the Settings app and open Chrome again.

Option 2 – Try to update or rollback the Graphics driver

You can try to update your Graphics card driver using the Device Manager in your computer to resolve the blank dialog boxes problem or you can also go directly to the website of your graphics card manufacturers like NVIDIA, Intel, or AMD and go to the section called Drivers then check if there’s a new available update – if there is, download and install it. To update your Graphics driver via Device Manager, refer to these steps:

• First, boot your computer into Safe Mode.
• After that, tap the Win + R keys to launch Run.
• Type in devmgmt.msc into the box and tap Enter or click OK to open the Device Manager.
• After that, a list of device drivers will be displayed. From there, look for the Display Adapters and click on them.
• After that, right-click on each entry under the Display Adapters and select the “Uninstall Device” option from the menu.
• Now restart your computer.
• After restarting your computer, go to the Settings app and Check for Updates in the Windows Update section.

Note: If updating the Graphics driver didn’t fix the problem, you can also try to roll back to its previous version and see if that helps.

Option 3 – Try to disable the Hardware Acceleration

For better performance, Google Chrome uses the Hardware Acceleration by default. Unfortunately, there are just some cases when your hardware, GPU to be specific, might not be able to cope with the requirements, resulting in the black screen issue. And if this is your case, you should try to disable the hardware acceleration from your Google Chrome browser settings panel. To do so, follow the steps below.

• Open the Google Chrome settings page.
• Click on the Advanced button to get more options.
• Look for the option called “Use hardware acceleration when available” and then disable it by toggling the button to the left.
• After that, check if the screen flickering issue in Chrome is fixed.

Option 4 – Try to disable “Smooth Scrolling” in Chrome

Disabling “Smooth Scrolling” in Chrome might also help you fix the issue. To do so, follow these steps:

• Open Chrome and type “chrome://flags” and hit Enter.
• Next, look for a flag named “Smooth Scrolling”. You can scroll down until you find it or search it in the Search Flag bar. Note that Smooth Scrolling is enabled by default in the newer versions of Chrome.
• After that, select the drop-down menu and select Disabled.
• Then click on the “Relaunch Now” button.

In their search for making Windows, a better operating system Microsoft has come up with an insider program that will collect telemetry and send it to Microsoft in order to provide enough information to make a better OS. Being in an insider program is per choice basis and it is not forced to anyone. This guide will cover how to turn off the insider program since its constant updates and telemetry can slow down the internet. So if you decided that you no longer want to be part of this program here is how to turn it off.

• Press ⊞ WINDOWS + R to open the run dialog
• Type in dialog gpedit.msc and press ENTER
• You will find yourself in the Local Group Policy Editor Window. Inside windows find: Computer Configuration > Administrative Templates > Windows Component > Windows Update > Windows Update for Business
• Move to the right pane and double-click on the Manage Preview Builds option
• Inside the Manage Preview Builds window, check the Enabled radio button
• Go to the Options section, and using the drop-down menu, set the preferred release channel
• Select Apply and then OK

Computers viruses, worms, ransomware, etc. are kinds of malicious software that no user should take lightly. On several occasions, we have touched upon security steps that each user should take in order to protect its identity and data. Sadly sometimes even when all precautions are taken some malware can still slip through and wreak havoc. Today we are looking at some of the worst or the best, depending on your view that has indeed wreaked plenty of havoc.

10 worst computer viruses in history

In the list of the 10 most famous computer viruses below, we show the costs, dates, reach, and other key facts. First a note about terms: we use the words “virus” and “worm” interchangeably because most readers search for them that way. But there’s a subtle difference that we explain after the list.

1. Mydoom – $38 billion

The worst computer virus outbreak in history, Mydoom caused estimated damage of $38 billion in 2004, but its inflation-adjusted cost is actually $52.2 billion. Also known as Novarg, this malware is technically a “worm,” spread by mass emailing. At one point, the Mydoom virus was responsible for 25% of all emails sent. Mydoom scraped addresses from infected machines, then sent copies of itself to those addresses. It also roped those infected machines into a web of computers called a botnet that performed distributed denial of service (DDoS) attacks. These attacks were intended to shut down a target website or server. Mydoom is still around today, generating 1% of all phishing emails. That’s no small feat considering the 3.4 billion phishing emails sent each day. By that figure, Mydoom has taken on a life of its own, infecting enough poorly-protected machines to send 1.2 billion copies of itself per year, 16 years after its creation. Though a $250,000 reward was offered, the developer of this dangerous computer worm was never caught. Wondering what makes the world’s most secure computers so safe? See the Tech@Work guide: Upgrade to the World's Most Secure and Manageable PC

2. Sobig – $30 billion

The 2003 Sobig computer virus is actually another worm. It is second only to the Mydoom virus in its scope. The $30 billion figure is a worldwide total, including Canada, the U.K., the U.S., mainland Europe, and Asia. Several versions of the worm were released in quick succession, named Sobig.A through Sobig.F, with Sobig.F being the most damaging. This cybercriminal program masqueraded as legitimate computer software attached to emails. It disrupted ticketing at Air Canada and interfered with countless other businesses. Despite its widespread damage, the creator of the successful bug was never caught.

3. Klez – $19.8 billion

Klez is a close third on the list of the worst computer viruses ever created. With nearly $20 billion in estimated damages, it infected about 7.2% of all computers in 2001, or 7 million PCs. The Klez worm sent fake emails, spoofed recognized senders and, among other things, attempted to deactivate other viruses. As with other viruses and worms, Klez was released in several variants. It infected files, copied itself, and spread throughout each victim’s network. It hung around for years, with each version more destructive than the last. Windows has come a long way since most of the computer viruses on this list hit the web. Thankfully, built-in protection with Microsoft Defender is always on the watch.

4. ILOVEYOU – $15 billion

The year 2000’s ILOVEYOU virus worked by sending a bogus “love letter” that looked like a harmless text file. Like Mydoom, this attacker sent copies of itself to every email address in the infected machine’s contact list. Shortly after its May 4 release, it had spread to more than 10 million PCs. The virus was created by a college student in the Philippines named Onel de Guzman. Lacking funds, he wrote the virus to steal passwords so he could log into online services he wanted to use for free. He reportedly had no idea how far his creation would spread. This virus is also known as Loveletter. Need to up your remote work security game before there’s another entry on the list of most deadly computer viruses? See our guide: How to Work Remotely and Securely

5. WannaCry – $4 billion

The 2017 WannaCry computer virus is ransomware, a virus that takes over your computer (or cloud files) and holds them hostage. The WannaCry ransomware ripped through computers in 150 countries, causing massive productivity losses as businesses, hospitals, and government organizations that didn’t pay were forced to rebuild systems from scratch. The malware raged like wildfire through 200,000 computers worldwide. It stopped when a 22-year-old security researcher in the U.K. found a way to turn it off. Computers with out-of-date operating systems were hit especially hard. That’s why security experts always recommend updating your systems frequently.

Ransomware strikes again

In September 2020, one of the potentially largest computer virus attacks in medical history hit Universal Health Services. The U.S. hospital chain, which has more than 400 locations, was reportedly struck by damaging ransomware. The attack forced the cancellation of surgeries and made healthcare workers switch to paper records.

6. Zeus – $3 billion

The Zeus computer virus is an online theft tool that hit the web in 2007. A whitepaper by Unisys three years later estimated that it was behind 44% of all banking malware attacks. By then, it had breached 88% of all Fortune 500 companies, 2,500 organizations total, and 76,000 computers in 196 countries. The Zeus botnet was a group of programs that worked together to take over machines for a remote “bot master.” It originated in Eastern Europe and was used to transfer money to secret bank accounts. More than 100 members of the crime ring behind the virus, mostly in the U.S., were arrested in 2010. It’s not as prominent today, but some of the virus’ source code lives on in newer botnet viruses and worms. Zeus caused documented damage of $100 million. But the real cost in terms of lost productivity, removal, and undocumented theft is undoubtedly much higher. A $3 billion estimate, adjusted for inflation, puts this virus at a cost of $3.7 billion in today’s dollars.

7. Code Red – $2.4 billion

First observed in 2001, the Code Red computer virus was yet another worm that penetrated 975,000 hosts. It displayed the words “Hacked by Chinese!” across infected web pages, and it ran entirely in each machine’s memory. In most cases it left no trace in hard drives or other storage. Financial costs are pegged at $2.4 billion. The virus attacked websites of infected computers and delivered a distributed denial of service (DDoS) attack on the U.S. White House’s website, www.whitehouse.gov. In fact, the White House had to change its IP address to defend against Cod Red. Can your printer get a virus? See our cool infographic: The State of Printer Security

8. Slammer – $1.2 billion

The SQL Slammer worm cost an estimated $750 million across 200,000 computer users in 2003. This computer virus randomly selected IP addresses, exploiting vulnerabilities and sending itself on to other machines. It used these victim machines to launch a DDoS attack on several internet hosts, significantly slowing internet traffic. The Slammer worm hit banks in the U.S. and Canada especially hard, taking ATMs offline in many locations. Customers of Toronto’s Imperial Bank of Commerce found themselves unable to access funds. The attack reared its ugly head again in 2016, launching from IP addresses in Ukraine, China, and Mexico.

9. CryptoLocker – $665 million

Thankfully, ransomware attacks like the 2013 CryptoLocker virus have dipped since their 2017 peak. This malware attacked upwards of 250,000 machines by encrypting their files. It displayed a red ransom note informing users that “your important files encryption produced on this computer.” A payment window accompanied the note. The virus’ creators used a worm called the Gameover Zeus botnet to make and send copies of the CryptoLocker virus. According to a report by security firm Sophos, the average ransomware attack costs a business $133,000. If we estimate that CryptoLocker hit 5,000 companies, that would put its total cost at $665 million. Where will cybersecurity go next? See our guide: The Future of Cybersecurity

10. Sasser – $500 million

The Sasser worm was written by a 17-year-old German computer science student named Sven Jaschan. He was arrested at the age of 18 in 2004 after a $250,000 bounty was posted for the computer virus’ creator. A friend of Jaschan’s tipped authorities that the youth had penned not only the Sasser worm but also the damaging Netsky.AC attack. Jaschan was given a suspended sentence after it was found he was a minor when he wrote the malware. The Sasser worm crashed millions of PCs, and though some reports put damages at $18 billion, the relatively low infection rate suggests a more likely cost of $500 million. Other notable viruses The top 10 worst computer viruses above are just the ugly tip of a gargantuan digital iceberg. With a million new malware programs popping up every 3 years, we may miss the forest for a few outstanding trees. Here are just a few more viruses that have wreaked havoc over the years: Mimail: This worm tried to harvest data from infected machines to launch a string of DDoS attacks, but was relatively easy to remove. Yaha: Yet another worm with several variants, thought to be the result of a cyber-war between Pakistan and India. Swen: Written in C++, the Swen computer worm disguised itself to look like a 2003 OS update. Its financial cost has been pegged at $10.4 billion, but not reliably. Storm Worm: This worm showed up in 2007 and attacked millions of computers with an email about approaching bad weather. Tanatos/Bugbear: A 2002 keylogger virus that targeted financial institutions and spread to 150 countries. Sircam: A computer worm from 2001 that used counterfeit emails with the subject line, “I send you this file in order to have your advice.” Explorezip: This worm used fake emails to spread to every machine on thousands of local networks. Melissa: The most dangerous computer virus in 1999, Melissa sent copies of itself that looked like NSFW pics. The U.S. FBI estimated cleanup and repair costs at $80 million. Flashback: A Mac-only virus, Flashback infected over 600,000 Macs in 2012 and even infected Apple’s home base in Cupertino, Calif. In 2020, there’s now more malware on Macs than on PCs. Conficker: This 2009 virus still infects many legacy systems and could do significant damage if it ever activates. Stuxnet: This worm is reported to have destroyed Iranian nuclear centrifuges by sending damaging instructions.