On a side note, I have a mildly interesting story about a student of mine who was about to do a complete reinstall on a working copy of XP in our lab. Since we were going to completely trash the system, he asked if he could see what would happen if he deleted the registry. (For those of you who don't know, the registry is a database containing every single configuration item on which the XP installation and its applications depend on including drivers.) BEFORE I SAY ANYTHING ELSE, UNLESS YOU WANT TO KILL YOUR XP INSTALLATION, DO NOT DO THIS!
First of all, deleting the registry was not an easy feat. We used regedit, but it still took a while. Eventually, most everything on the system stopped working, even the keyboard and the mouse. We did still have video, though, so we stared at it for a second to see if it would implode too. That was when the scary thing started to happen. It was like watching Michael Myers come back from the dead. The registry started rebuilding itself, and within 5 minutes, we had a fully functioning XP installation again. Of course in another ten minutes we were reformatting the drive for a Linux installation, so we won in the end.
-Dave