Can anyone tell me if it's possible to make windows prompt users for credentials when opening certain or all programs? All help is greatly appreiciated.

It seems to methat you can simplyenable UAC (User Account Control) in Windows Vista, and if the user does not have sufficient permission to launch the program, it requires to enter credential. This helps ensuring the system security. For more information about UAC, please check the following link: How to use User Account Control (UAC) in Windows Vista http://support.microsoft.com/kb/922708