Have you run any anti virus and anti spyware scans?
Whenever I attempt to open My Computer, the browser will look for it for a very long time (1-2 minutes), and then finally either find it or just give me a blank screen. Also, when attempting to open iTunes and Paint, it takes a long time to open the applications. Finding the folders through explorer takes no time, but opening the applications themselves does.
I am running Windows XP Media Center Edition, Version 2002, Service Pack 2. It is manufactured by eMachines, T6520.
Also: In System properties, it seems that my PC is named "potato", although I haven't given it a name. Is that bad?