[FourPenguins]

Originally Posted by martin417

If you can boot from the Windows CD, you can do a "repair install". after you boot, DO NOT GO TO THE REPAIR CONSOLE, go ahead And tell it to install windows. It will then do a disk check and tell you that windows already exists on this partition and ask if you want to repair. Say yes. It looks like it is reinstalling windows, but it's not. It will replace all system files. I think it will return you to the service pack level of the install CD, not sure on that. If you google "repair install XP" you should find lots of info.

Good luck.

I second this method. It is the most reliable way to fix an unknown Windows OS problem, especially stemming from a corrupted file. The linux junkies can do what they want, but this is a nice tool from Microsoft that I've found easy to use and invaluable.
Once you're back up and running, I suggest you do all the regular maintenance (scandisk, defrag, antivirus, antimalware, registry check, and uninstall programs you don't use.)