The Windows System File Checker utility can be used to scan and then automatically replace any corrupt or missing system files. In fact, this tool should be part of the essential tool kit for every computer user.
When Windows programs are not running or operating as they should do e.g. perhaps double clicking a file does not open the program that should open it, or perhaps you can’t even boot your PC, then System File Checker may be able to help you to get things working well again.
If you can boot to the Windows Desktop and want to repair a damaged Windows file (i.e. miscellaneous operational problems) the time has come to use the System File Checker tool (SFC.exe). This will determine which file is causing the issue, and then try to replace that particular file.
To run this tool open an elevated command prompt. To do this, click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
At the command prompt, type sfc /scannow (leave a space between sfc and /scannow) and then press Enter.
NOTE: The /scannow option is the most commonly used switch for the sfc command that can fix multiple problems with Windows system Files.
System File Checker may prompt you for a Windows Installation disc, which is either the disc you used to install or upgrade Windows or the system recovery disc provided by your computer manufacturer. So have your disc handy, just in case it’s needed. System File Checker will only ask for this disc if corrupt system files have to be replaced by fresh ones from the Installation CD/DVD.
System File Checker fixes what it can. Mostly, it moves through its processes and displays the percentage completed like 10%, 30% and 50% as it goes. When it completes it shows ‘Verification 100% complete’.