The “Unknown Hard” error that keeps on appearing in Windows 10 can put users in an unpleasant situation. This kind of error leads to the freezing of the taskbar, blackening of the screen, and sudden disappearance of the icons on the Desktop. And each time you try to open Windows, the system will only give you an error message saying that it’s a critical error and some applications like Start and Cortana won’t work.
Upon analysis, it seems that the “sihost.exe” is not responding and that it is the one that’s causing the c000021a Unknown Hard error to pop up. Sihost.exe files represent the Shell Infrastructure Host which is an essential component in the Windows operating system. The Windows Shell Infrastructure Host is primarily responsible for handling some graphical elements of the operating system interface such as the Start menu and the taskbar transparency. And so if the Shell Infrastructure or Sihost.exe has stopped, has been removed, or corrupted, you will most likely have issues with the overall functionality of the Windows operating system and you’ll get the Unknown Hard error
In addition, the ctfmom.exe Unknown Hard error may also occur due to incompatible drivers installed on your PC. Ctfmom is a process that identifies inputs such as handwriting, languages, and many more. It’s the one that controls the functions of background behavior. To resolve this issue, you need to first try to identify which application is the one that’s running the sihost.exe file. And if needed, you need to either update or reinstall or completely uninstall the problematic application.
The SFC Scan or System File Checker, us a built-in utility in Microsoft Windows that can be found in the C:\Windows\System32 folder. This tool allows users to scan and restore any corrupted system files in Windows that might be causing the Unknown Hard error to appear. Before you use this tool, make sure to find out whether the sihost.exe on your computer is a Trojan that you have to remove or if it’s a file that belongs to a trusted Windows application. Once you have that sorted out, follow the steps below.
The command will start a system scan which will take a few whiles before it finishes. Once it’s done, you could get the following results:
You can also try using System Restore. This is one of the ways you can use it to back up your PC. Since restore points are created automatically each week by System Restore, you can use System Restore to restore your computer back to an earlier good point in time.
Putting your PC in a Clean Boot state can help you diagnose and troubleshoot the issues in your system. During this state, you can start the system with a minimum number of drivers and startup programs that will surely help you in isolating the root cause of the Unknown Hard Error.
After putting your PC in a Clean Boot State, try creating a system restore point and see if the problem still occurs. Clean Boot troubleshooting is designed to help you isolate the problem. For you to execute a clean boot troubleshooting, you must do a couple of actions (the steps are given above) and then restart your PC after every action. You might have to disable one third-party app after the other to really isolate the issue. And once you’ve narrowed down the problem, you can either disable the third-party app that’s causing the problem or remove it. Note that you must switch your PC back into the Normal Startup mode after you’re done troubleshooting the problem. Here’s how you can do it:

Boost My PC is a program developed by 1.0.2.6. During setup, a scheduled task is added to Windows Task Scheduler in order to launch the program at various scheduled times (the schedule varies depending on the version). When installed, it will add a context menu handler to the Windows shell in order to provide quick access to the program.
Boost My PC presents itself as a legit PC speed-up utility, it scans your computer for problems and displays errors that need to be fixed. Upon accepting to fix these alleged errors, you are asked for a Payment in order to activate this product for a few months.
Many anti-virus scanners have marked this application as a Potentially Unwanted Program, and while Boost My PC is not so harmful on its own, it comes bundled with other Potentially Unwanted Programs that might harm your computer.
New Tab Aid is an extension for Google Chrome. It is published by Spigot Inc. It is classified as a potentially unwanted browser hijacker as it injects Yahoo search into your new tab windows. This extension also adds recently viewed tabs under the search bar. It also redirects all your searches to Yahoo instead of your default browser search engine. It is often found bundled with other software found on the internet and not installed directly by the user. For these reasons, numerous anti-malware utilities flag New Tab Aid as potentially unwanted or malicious.
This is a common Device Manager Error Code that users encounter. It is commonly found on all Windows 2000 and later versions of Windows operating systems. Error Code 36 is usually prompted by the following message:
"This device is requesting a PCI interrupt but is configured for an ISA interrupt (or vice versa). Please use the computer's system setup program to reconfigure the interrupt for this device. (Code 36)"
Error CausesError Code 36 occurs when there is a failure in IRQ translation due to your Windows operating system getting corrupted. This is caused due to a number of triggers, such as:
When programs are removed excessively, some programs are not removed completely and create problems in your computer’s registry.
Also, due to the presence of malware and spyware and other causes mentioned above, your computer registry builds up errors with the time that leads to slowing your PC, time lags, and even result in crashes and freezes.
Error Code 36 can cause internal and external components to malfunction or experience time lags such as DVD drive or printer and hence can severely affect your entire PC.
Error Code 36 is a severe PC error and any attempt at fixing the error must be approached with extreme caution for your PC to start functioning properly again. Here are two methods to fixing your PC.
Changing the IRQ reservation settings is the best way you can rely on to fix the error code. You can do this by changing the BIOS settings of your PC.
The BIOS stands for ‘Basic Input/Output System’ and is the program of your PC’s microprocessor that allows your PC to boot after you switch it on.
Caution needs to be exercised before changing the BIOS settings of your PC. This is because every PC’s BIOS version differs from another and any wrong attempt to change the settings may make matters worse.
It is therefore recommended to refer to hardware documentation that you received with your PC or motherboard and check for the model number and details of your PC’s motherboard.
Only after you have checked and confirmed all the details, should you use the specific BIOS settings required to configure your IRQ reservations?
Error Code 36 isn’t an easy error to remove.
While changing the BIOS settings can work to restore your PC, it may create a whole lot of inconvenience for finding the time and effort to check the hardware documentation details and attempting to change the specific settings and especially, if your PC does not support the options to change IRQ reservations.
Given the high risks of fixing such an error, you can also install software that enables you to fix your slow PC at the click of a few buttons.
Programs such as DriverFIX can enable you to download and replace your outdated drivers with new updated ones without you having to look for them. It will detect which drivers to download based on your PC’s motherboard version from the program’s database and can get rid of error code 36.
Click here to download DriverFIX and remove error code 36 and any other type of Device Manager error from your PC.
in the command prompt you need to type the next command:
dir \search term* /swhere search term* is well, what are you searching for. Now if you are looking for a specific file this command is straightforward, you just change search term* with file_name.extension and there you go, but know that this command can be used to be more powerful, for example, you can find all JPG files in your drive by typing dir \*.jpg /s or all files named work by typing dir \work.* /s " * " is a so-called joker sign, it replaces several characters with any in a given string, meaning that dr*s will give you all results with the first 2 letters dr and last one s. Use this to specify better search results and you will get your files in no time.
Disk Write Error in Steam is thrown at you while you try to download or update the game in your library. If you are an unfortunate user of Steam that has encountered this error do not sweat, the error is usually tied to permission in windows or file corruption and not to hardware issues and can be easily resolved.
In this guide, we will go through solutions for this specific error and it is advisable to go through solutions as they are presented since they go from the easiest and most common issues.

The easiest and quickest way of resolving this issue is just a simple restart of the Steam client. Just completely quit Steam and they run it again, if this has not solved the issue try rebooting your PC. In most cases, this can solve the issue since this error is known to be introduced with some communication issues with OS (Windows)
Disk write permissions could also cause this error because if by any chance the Steam library folder has been set or changed to the read-only client would be unable to write anything in it. To easily solve this issue completely exit the Steam client and rerun it as administrator. Just right-click on it and select Run as Administrator. If this has solved your issue run Steam always as an administrator.
To run always as an administrator right click on the steam executable, go to properties, and inside properties go to the compatibility tab. In the compatibility tab check run as administrator and click on OK.
If for any reason cache has become corrupted there is a big chance that this might be an issue why there is a disk drive error in Steam. To clear download, cache goes into your client, and on top drow down menu click on steam. Find and open settings and inside go to the downloads tab. Locate a clear download cache and immediately you will be prompted to restart Steam. After restart, you will be asked to login into steam and the issue with disk write should be gone.
Library folder issues can also be the source of disk write annoyance so let's repair them. Click steam in the top left and go to the settings. Locate and click on Downloads and then go to Steam library folders. You will be here shown all disk drivers you are using for steam games and all of the games that are downloaded.
Select the game you are getting errors with and click on three dots on the far right. From the menu choose the repair folder option. Take note that the more games you have installed, the more time the repair process will need.
Sometimes the issue is not at your end at all, servers can experience problems and outrages and this can directly reflect at your end with a disk write error. If any of the previous solutions have not resolved the issue this is the next logical step to try. If the server is facing issues then changing the download server will resolve the issue at your end.
Click on settings in the top drop-down menu and then click on the Steam library folder. Find the downloads page and then click on download region, Choose another server than one nearest to your location since that's what will Steam choose by default.
powercfg –lastwakeOnce you enter the command given above, it will show you the last device that woke your PC up. After that, you need to type in the next command:
powercfg –devicequery wake_armedAfter entering the command, it will show you a list of all the devices that could wake your PC up. The goal in running these commands is to understand the reason what’s really causing your PC to turn on and see the reason is on the hardware level or not. Here are a couple of options you can try if your Windows 10 PC turns on by itself.