Always strive to learn something useful. --Sophocles

There's a program for Windows machines, I'm not sure if it'll work for all Intel-based boxes, called Deep Freeze. We used it at the university when I was a lab aide. It locks the image and whenever the compute reboots, it goes back to the locked image. Theoretically it can't be infected with malware, but it's been a while since I've used it and the malware scene has changed considerably since then.