Heh, type control-alt-delete *twice* at the prompt for a password, try:
"Administrator" as the user name, no password, if that doesn't work try "Owner" as the user name and no password. You'd be surprised how often that works on Windows machines (I used to fix Gateway laptops for a living, and morons who didn't provide a password and expected us to fix their laptop got p0wned by this method). Or I just re-imaged their drives and gave them a Factory-Fresh Reload (FFR).
We also had password cracking utilities which you can find online for getting into Windows XP easily enough. Usually requires burning a special CD to boot from tho.
There was even a special cracker for fingerprint scanners, but that was kept protected by the supervisor in case us peeons somehow made a copy and posted it to the interweb.