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Third-party programs, virus attacks, human error – there are many possible reasons behind a corrupted system file. If you are getting an error something like “file missing or corrupted” message on Windows, performing a system scan for corrupted or missing files is probably the best way to begin the troubleshooting.

Bootrec, chkdsk, I noticed it changed how it looked on the device manager. /scannow' 12. Are faulty and can't repair,but thats my dvd drive. The root cause determined by Startup Repair was 'No OS files found', even though when I used a Ubuntu LiveCD and from the Open Additional Drives prompt in 'Recover from System Image' or something like that on the Windows Install CD to view my computer, strangely enough, all of the files and folders, even my gaming files that were interrupted.

There are a couple of tools available to fix various issues of Windows but it’s hard to find out a good tool to troubleshoot and fix missing or corrupted system files.

Scanning your PC for corrupted and missing files is relatively simple in Windows 7. You just need to open elevated prompt and execute a command to scan and automatically fix corrupted or missing system files.

In this guide, we will show you how to repair Windows 7 system files without using any third-party tools.

NOTE 1: If you are on Windows 10, please refer to how to repair corrupted system files in Windows 10 article.

NOTE 2: We also recommend you perform a complete scan of your PC using good antivirus software to make sure that your PC isn’t infected in any way. If you have one or more previously created system restore points, restoring your PC to a previously created restore point might also fix the file corruption issue.

Repair system files in Windows 7

Step 1: Type command prompt in Start menu search box and then hit Ctrl + Shift + Enter to launch the Command Prompt with administrator rights. Alternatively, go to Start, All Programs, Accessories, right-click on Command Prompt and then select Run as administrator option.

Step 2: Click Yes if you are prompted with UAC (User Account Control) box.

Step 3: Once the Command Prompt opened, type sfc /scannow and hit enter. This command scans the integrity of protected system files and then repairs if problems found.

Step 4: The process may take a few minutes. Once done, you are good to close the Command Prompt.

You can also type just sfc in the Command Prompt to know more about sfc commands.