Verify / Repair the protected system files of Windows

After installing or uninstalling a program, protected system files of Windows can be modified or deleted. Missing a file system can lead to many failures and find such a file can be difficult. Fortunately, Windows XP and Vista includes a utility called System File Checker (SFC) to check the system files and if one is damaged or missing, the utility is responsible to replace the original that is CD in your Windows installation.

Click "Start", "Run ..." then type "sfc /scannow"

If the SFC utility is a system file missing or damaged, the installation CD of Windows may be requested.

In addition, other commands exist for the use of SFC:

• sfc /scanonce: check all protected system files once at the next reboot
  
• sfc /scanboot: check all protected system files on every boot
  
• sfc /revert: Get the scan to the default settings
  
• sfc /purgecache: Empty the cache files and verify protected system files immediately
  
• sfc /cachesize = X: Sets the size of the cache files (where X is a value)