Use the System File Checker tool to repair missing or corrupted system ...
If some Windows functions aren't working or Windows crashes, use the System File Checker to scan Windows and restore your files. Though the steps below might look complicated at first glance, just follow them in order, step-by-step, and we’ll try to get you back on track. Run the System File Checker tool (SFC.exe)
Remove malware from your Windows PC - Microsoft Support
The Microsoft Defender Offline scan will automatically detect and remove or quarantine malware. Learn how to remove malware from your PC. Use Microsoft Defender Antivirus in Windows 10 or Windows 11 to scan your PC for malware, viruses, or other threats.
Applies To: OneDrive (home or personal), OneDrive for Windows
Remove specific prevalent malware with Windows Malicious Software ...
The Windows Malicious Software Removal Tool (MSRT) helps remove malicious software from computers that are running any of the following operating systems: Windows 11. Windows Server 2022. Windows 10. Windows Server 2019. Windows Server 2016. Windows 8.1. Windows Server 2012 R2. Windows Server 2008 R2. Windows 7. Windows Server 2008.
Use System Restore - Microsoft Support
Use System restore to make restore points when you install a new app, driver, or Windows update, and when you create a restore point manually. Restoring won’t affect your personal files, but it will remove apps, drivers, and updates installed after the restore point was made.
Automatically fix Windows security issues - Microsoft Support
Follow these steps to automatically diagnose and repair Windows security problems by turning on UAC, DEP protection, Windows Firewall, and other Windows security options and features. Select the Download button on this page.
Fix problems that block programs from being installed or removed
The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs. It also fixes corrupted registry keys. First, you'll need to download the troubleshooter. Download troubleshooter.
Update drivers manually in Windows - Microsoft Support
Learn how to update drivers in Windows using Device Manager to update or reinstall a driver.
How to start a scan for viruses or malware in Microsoft Defender
You can start a scan for malware any time you like. Note: Microsoft Defender currently offers anti-malware on Windows, Android, and macOS. From the Microsoft Defender dashboard. If you want a deeper scan, instead of selecting Quick scan in step 3, select Scan options and choose the type of scan you want.
Applies To: Microsoft Defender on Android, Microsoft Defender on Mac, Microsoft Defender on Windows
Getting started with anti-malware in Microsoft Defender
Microsoft Defender's real-time anti-malware protection runs whenever your device is on, keeping an eye out for malicious activity. Microsoft Defender will also run quick scans of your device on a daily basis, in case anything manages to elude the real-time protection.
Applies To: Microsoft Defender on Android, Microsoft Defender on Mac, Microsoft Defender on Windows
How to prevent and remove viruses and other malware
Discusses how to remove viruses, spyware, rogue software, or malware using Microsoft Security Essentials, Microsoft Safety Scanner and Microsoft Defender Offline.