Here is just a Basic Guide on how to a perform System File Scan within Windows 7 & Vista;
(Please note XP user's will need the Install CD to perform this action)
The System File Checker will look for any system files/.dll file's that are corrupt and will attempt to fix these normally following a re start of your computer, this is a very useful tool should you be experiencing any issues with windows software/registry/system file issues.Go to Start > All Program > Accessories > Right Click Command Prompt and Run As Administrator;
Type In sfc /scannow
and hit enter
then let it complete the scan.Screenshot 1Screenshot 2Screenshot 3
This can also be run in safemode too by selecting Safemode with command prompt privilage.Hope you found this useful!