Most install any number of spyware that slows a machine to a crawl.
If you can reveal the name, then you may find out what's up.
My son has a rather new Gateway with a celeron processor, 256 RAM and running Won XP home. Very little has been added - a file sharing program of course. It ran pretty fast out of the box, but is now slow - even opening the control panel is slow. I don't think a celeron should run slow like this, but who knows. We have defragmented, all windows updates are current and same for Norton Anti-Virus. Anyone have any tips for speeding this thing up?