security on network

I am in a small company as a computer administrator.In xp there is a srcurity
available that no one can install program from server without administrator
login. But in vista everybody can install program from server in their own
login. I heard that for security it may some thing do but what to do that I
don't know. So please help me & get the answer as soon as possible.

Just I want that no one can install program without administrator login.
Administrator login necessary for installing program from server.