You have to resist the evil temptation and get XP, using Vista is supporting dictators and terrorists.
That said, I turned the UAC off but then Whacker says my PC is as open as a barn door(a pretty well-running barn door though, I like to think the hackers keep it running because it's important to them somehow ).
What it does is when you copy files into your program files folder, it copies them elsewhere but shows them in the program files folder but your game or other program won't find them there as they aren't really there. You may also not be allowed to edit any files there etc. It should work fine until you start modding games, changing .ini files etc. and I'm obviously too much of a noob to tell you how to do that without turning the whole thing off. *runs into corner in unimaginable shame*