I found this neat little tool to help improve your computer's performance while playing games or running other demanding applications. It's a free program called Game Booster from IObit. It basically just disables unneeded Windows services for you with one click.
When I ran the program and hit the 'Switch to Gaming Mode!' button, it killed all the unnecessary services and even offered to shut off my Anti-virus program and Vista Sidebar. Yes you can do this all manually, but it would take several clicks and a few minutes to do. This application does it quickly and will just as quickly turn everything back on when you hit 'Back to Normal Mode', including your Anti-virus and sidebar. PLEASE remember to return to Normal Mode before you start surfing the internet again! I must admit this program will NOT turn your 1.8 ghz AMD Sempron into a gaming monster. But it does certainly stop some of the background processes running on your computer, to help you squeeze every last FPS [frame per second, for you non-hardcore gamers 
] out of your computer.
According to IOBit, you can use this software on Windows 2000, XP, Vista, and Windows 7.
You can check out this program here at IOBit's website: http://www.iobit.com/gamebooster.html
