edja4547 :
critical updates will not install, checks come back with missing or corrupt files op sys was upgraded
from 7 to 8 via microsoft no recovery disk
First try System File Checker
Winkey plus 'X'
Choose Command Prompt (Admin)
Type
sfc /scannow then
Enter
It finds and fixes errors in Windows, but doesn't always report them. Run it and see if the fault disappears after re-booting your system
If corrupt files are found that can’t be fixed, try
Dism /Online /Cleanup-Image /RestoreHealth (Observe spaces before
/)
Re-run SFC
To view CBS Log
findstr /c:"[SR]" %windir%\logs\cbs\cbs.log >sfcdetails.txt
Search C drive for sfcdetails.txt or navigate to C:\Windows\System32 and scroll down.