It sounds like you didn't see a complete installation there. The easy tool to try there is the system file checker to see if that will replace the needed files before anything else. With the XP installation disk in the drive simply go to Start>Run and type "sfc /scannow" in at the prompt and press enter. The bilk of the main system files will be verified and repaired and replaced as needed. It will take several minutes to complete. But give that a try first.
Just reinstalled XP (Again!)
ANY help is much appreciated.