The SFC (System File Checker) scans all protected system files and replaces them with correct Microsoft versions.
> Close any open programs on your Desktop
> Click on the Start button
> Click Run
> Type this in the Run box: SFC /SCANNOW
> Click the "OK" button
*It may take from 30 minutes to a couple of hours to finish. It will be faster if you do not use the computer during the process.
> Once complete, the Run window will close and may resume other activities