AskAdmin is a free tool which prevents users running the applications or opening file types (bat, cmd, reg etc) that you specify.
This protection can be removed with a click, or you're able to run the application directly from AskAdmin's interface.
Blocking an individual program is as easy as pointing AskAdmin at its executable. If any user - even an administrator - tries to run that file afterwards, a message explains that they don't have permission.
It's also possible to block an application for a specific user only.
Your block list can be exported for use on another computer, perhaps handy if you want to prevent your children accessing programs on your PC and laptop.
It's not infallible - at all - but AskAdmin is a simple and lightweight tool which could help control what non-technical users can do on your PC.