[gonzo]

Sounds like a memory (RAM) issue. Try clearing off anything you don't need on the hard drive as well though as if that's too full it'll also cause problems, especially on XP.

Hit cntrl-alt-del and get task manager up. This will show you what programs are running and how much resource they're hogging, likely you'll have various items you aren't even aware are running and prob don't need. Kill them off and you should see some improvement.