System File Checker (SFC) by Microsoft
System File Checker (SFC) is a built-in tool by Microsoft Windows, used to scan and repair corrupted or missing system files, including .dll files.
You must open the Command Prompt (cmd) as an Administrator to use this feature.
Open the Command Prompt
Scan only
C:\User\Username>sfc /verifyonly
Scan and fix errors
C:\User\Username>sfc /scannow
Purge cache and scan integrity
C:\User\Username>sfc /purgecache
Revert SFC changes
C:\User\Username>sfc /revert