Is it just MS based or can you mess with hardware? (Sounds like a troubleshooting class).

If you can mess with hardware, a little "clear" nail polish on some of the connectors for video/ram can do amazing things (I've actually been told by a student that the motherboard was dead when in fact it was the video and cache being "toast"). You can safely remove the nail polish with a non-acetone nail polish remover.

What about removing ntldr? replacing the SAM? infecting the machines with lots of "old" viruses (it's amazing what happens when you have something like 10 of them in one machine)?