Shut out OS temporarily?

My laptop is actually quite a powerful gaming PC for a laptop and can flawlessly run most games but... The only problem is it runs vista. Not that there's anything wrong with vista but honestly it's a cpu hog. I was just wondering if there was a program (besides gamebooster) that can temporarily shut down most of vista's processes that aren't really required for gaming. If possible I would like a way to completely shut out vista while I game.