Run the
System File Checker
Go to the Run box on the Start Menu (or the Windows key + R) and type in:
sfc /scannow ( sfc if not reconized) (Note that there is a space between sfc and /scannow)
This command will immediately initiate the Windows File Protection service to scan all protected files and verify their integrity, replacing any files with which it finds a problem.
In all likelihood you will be prompted to insert the Windows XP CD. Note that you'll need a CD with the same version of Windows as the one that's installed on your computer, i.e. you'll need an XP Home SP2 install CD if you have XP Home updated with service pack 2. If your XP install CD doesn't have service pack 2 you can create an XP SP2 CD using the following method :
http://www.winsupersite.com/showcase...slipstream.asp