It hardly seems worth discussing a Windows XP installation, but.... how much RAM do you have? It is probably an older machine so the available memory could be a real issue. Hard drive capacity vs available space is something else to check. Defrag. Check to see if your swap file is system managed. Make sure you don’t have multiple security software programs installed. Turn off system restore and turn it back on after you apply.
I degrag regularly. It indicates now that defragging is not necessary at this time.
I always leave something I've already tried, don't I?