I would write a simple vb app with a text box and command button and just have the system execute whatever is in the text box, it's just like having a command prompt. But, if you have even a descent IT team at your school, and you are running windows xp, there are some things that are much harder to get away with. For instance, they can do a hash on any executable that they don't want to run, say you try to execute the executable, even if it's renamed, it will produce the same hash, and the system will not execute it. I don't know, just my 2 cents.
dankydoo