For pre-XP, I just shut down everything via msconfig in Start Up. You only need three, some say two running. They are Explorer, Sys Tray and Sys. Manager ( I believe).
For XP, the problem there is all the Processes running in the background. You can shut down programs in Start Up and still have tons of Processes running "Behind the Scenes". I found two programs that shut down many of the non essential processes. One program is called XPAntispy and the other is called Startup Manager.
XPAntispy you can download from my site. It's on the second page of the CFS2 Tweaking guide.
http://www.brennt.com/hoppers/cfs2tweaking.htmlStartup Manager from here:
http://www.wheresjames.comBoth easy to use and free.
Systemax Sabre Ultimate gaming rig.
I got all the goodies and all the power I need to run anything thrown at me for the next two months!