My computer is slow all of a sudden, not like it used to be when I first had it. I only have norton antivirus running in the system tray and itunes occasionally. I have a 2.53 celly. 1gbram. winxp w/ sp2. 40gb harddrive w/ 50% free. Nvidia geforce fx5500. I installed spyware/adware removers, and they say my pc is fine. The socket is 478, so can I just buy a P4 3.2ghz(for example) and drop it in and go? Am I missing something? Thanks.