Commands to repair/troubleshoot basic windows issues.

To check Windows system files to check for corruption, run the following command in an administrator command prompt

sfc /scannow

More details on the command can be found here

After SFC scan, you can either restart and or start running the DISM commands

To check if Windows image can be repaired

Dism /Online /Cleanup-Image /ScanHealth

To check if Windows has any detectable corruption

Dism /Online /Cleanup-Image /CheckHealth

To repair Windows using DISM

Dism /Online /Cleanup-Image /RestoreHealth

More details on the repair and offline options can be found here