Despite Microsoft's best marketing efforts, you haven't yet upgraded to Vista. You still prefer your trusty old copy of Windows XP. And, despite your diligence in protecting your beloved XP machine from viruses and sneaky trojan horses, Windows is noticeably slower than when you first installed it. Don't panic -- there are a number of things you can do to get your XP system running faster.
Speed Up Windows XP - Wired How-To Wiki