How do I fix a missing or corrupted system file on my PC?

Check the System Restore Point
Windows System Restore may be able to fix the issue without any additional help. To check if a System Restore Point has already been created, follow the steps below.
Check the Windows File Integrity
Run a System File Check in Windows 10 to verify the integrity of system files and repair any corrupted files. To run a System File Check, use the following steps.
Repair Corrupted System Files with DISM Tool
If System Restore and SFC don’t do the job, you can always run the DISM tool to repair the corrupted system files. To use the DISM tool, follow the steps below.
Perform a Clean Boot
You can try to perform a clean boot to isolate the issue and to determine what is causing the corruption with your system files. To perform a clean boot, use the following steps.
Create a New User Account
If none of the above steps have worked, you can try creating a new user account in Windows 10 and transfer your data to it. To create a new user account and transfer the data, use the steps below.