CTRL + ALT + DEL Disable

[|roe]

Maybe also creating a dedicated user so UAC intervenes? However if users can get full control, I am not sure, but you can hit the inappriopiate person that knows to bypass UAC itself.

So far, creating a limited account and using the Administrator account to disable all of these should do the job. Don't know however, how you can not popup to not loose focus.

If it was a touchscreen like these PoS systems we see, would have been easier, however, in this case, some Malwares as already stated may provide a clue how to disable it, the only problem is the popup maybe.

The rest is complicated/complex and writing a driver (as suggested) for W$ can crash the whole system if is not written properly.