You know throwing in the windows CD, and reinstalling windows kept the desktop and user settings for the administrator user name and password
BUT
After I reinstalled windows it booted to a new clean desktop and set up a default admin user name. To restore his deskop and settings I just went into the control panel and switched his password without having to know it.
So even if you are the admin, a fresh load of windows will setup a new default admin on the box aside from the current one.
Seems to me as long as you have a XP pro CD you could take control of a computer with just the install cd and about 45 minutes of your time.