mb666 hello and welcome.
I'd make sure all programs, that you can, including browsers are closed. In start search box type CMD. In the list right click CMD and select 'Run as Administrator'.
Type sfc/scannow and press enter.
If you get an error that system file checker can't repair some files then try again a couple of times. If it persists not being able to repair, type 'exit' in CMD then reboot and try again.
See if that helps.