Try these scans which can find and repair issues:
File scans
Right click on the Start menu icon and from the revealed list choose 'admin command prompt'. Type:
sfc /scannow
press enter and await results
In the same command prompt and after the above scan has finished type:
dism /online /cleanup-image /restorehealth
Press enter and await results (longer this time).
If the first scan found files it could not repair but the second scan is successful, run the first scan again using the same command prompt box and this time it should repair the files found.