I eventually turned off User Account Control in Vista because it caused more problems than it prevented. A lot of older games that I wanted to install would insist on Administrator privileges, even though I was logged into the Administrator account (my comp has 2 accounts, apparently because Eddie and I share files with each other over the network). I'd always have to right click and "Run as Administrator", and even then it wouldn't work half the time. So I turned it off.
If you're having the same problems, a quick Google turned up
THIS.