I can understand wanting to restrict users abilities within the application.. I do that all the time. Have the user log in and based on the login they have access to certain areas/functions. Again.. what language are you writing your code in? I think, to prevent a user from using ANY other software, you'll have to go with a 3rd party application like zenworks on a Novell network. You will find it very difficult if not impossible to prevent users from using something other than your app.