I haven't tried this but it may be worth looking into. I found a program called Parental Lock Guard 1.2 on cnet's
www.downloads.com website. It states that it is a free program which will shut down the computer if something unwanted is done. The program is controlled by a system administrator's password. If you want to check it out, you can link directly to the program
here.
Again, I don't know if this will do what you need it to but at least it's another resource to check out.