Also if you have XP you can do some configuring to max it out.
go to
www.blackviper.com and check out his "XP service configurations"
basically he is explaining about the "services" that XP has running by default..services 99% of us dont need...like "alerter" "wireless zero config" "remote desktop help" blah blah....so basically you run "services.msc" and set the ones you dont need to "disable" or "manual".
He has a chart etc..I follow the "safe" config..except I leave the system restore on. (he turns it off but I dont)
JP