Re:Come on, did you really have to ask Slashdot? (Score 2, Informative)

I noticed someone else recommended Deepfreeze but if you work for a school system you probably don't have any money to accomplish this so you may want to try and use the Free Microsoft Shared Computer users toolkit

Documentation: http://www.microsoft.com/technet/prodtechnol/winxp pro/maintain/sct/default.mspx

Download: http://www.microsoft.com/windowsxp/sharedaccess/de fault.mspx