Faronics Corp. also have a couple of proggies out that might help you out a bit. And they are used in schools to protect their own computers. In particular Deep Freeze and Anti-Executable might be a couple of proggies you might want to look into. Good luck. ...griz
http://www.faronics.com/html/AntiExec.asp
http://www.faronics.com/html/deepfreeze.asp