The single most important thing Ive done to speed up WinXP pcs......
REMOVE AOL anything. The instant messenger installes sooooo much nonsense it slows a machine down to completet unusability.
If you must have it disable launch on startup via the preferences menu. Did this to my girlfriends laptop and it's like a new machine.
The startup items that are pre-installed slow a machine down so remove what you don't need.
