Remove specific prevalent malware with Windows Malicious Software ...
Use this tool to find and remove specific prevalent threats and reverse the changes that they made (see Covered malware families). For comprehensive malware detection and removal, consider using Windows Defender Offline or Microsoft Safety Scanner.
Uninstall or remove apps and programs in Windows - Microsoft Support
There are different ways to remove apps and programs, so if you can't find the one you're looking for, you can try another location. Note that some apps and programs are built into Windows and can't be uninstalled. You can try to repair a program first, if it's just not running correctly.
How to remove the PC Repair virus - Microsoft Support
While browsing the Internet or working on your computer after browsing the internet, you may notice that a new window titled PC Repair may open, you are asked to defragment your computer and then asked for personal information such as your email address.
List of security program cleanup and uninstall tools
Provides links to the uninstall tools and directions for many security programs.
Fix problems that block programs from being installed or removed
First, you'll need to download the troubleshooter. Download troubleshooter. If you see the File Download box when you start downloading, select Run or Open. The troubleshooter provides steps for you to follow. If a program isn't listed in the uninstall options, you'll be asked for that program's product code.
How to start a scan for viruses or malware in Microsoft Defender
Here's how to do that on Windows, Mac, or Android.
Applies To:
Microsoft Defender on Android, Microsoft Defender on Mac, Microsoft Defender on Windows
Use the System File Checker tool to repair missing or corrupted system ...
Use the System File Checker tool to repair missing or corrupted system files. When critical Windows system files are missing or corrupted, some Windows features may stop working correctly or Windows may stop responding altogether.
System Restore - Microsoft Support
With System Restore you can revert your PC's state to a previous point in time. This can be particularly useful when troubleshooting issues caused by recent changes, such as software installations, driver updates, or system settings modifications.
Automatically fix Windows security issues - Microsoft Support
Troubleshoots and fixes common issues with security and malware prevention in Windows.
How to use the Regsvr32 tool and troubleshoot Regsvr32 error messages ...
Regsvr32 is a command-line utility to register and unregister OLE controls, such as DLLs and ActiveX controls in the Windows Registry. Regsvr32.exe is installed in the %systemroot%\System32 folder in Windows XP and later versions of Windows. The 64-bit version is %systemroot%\System32\regsvr32.exe.