I really dont know mate? It could be so many things. Have you got all the update's for XP? I dont use XP as i cant stand it, but ive heard you really need to get all the background procceses to a minimum. Personally mate, id try 2000 pro. Ive never had any probs with this, but i have with 98 and ME. Also, you say you have 512 ram, xp eats this for breakfast! You could try and stick in a gig of ddr and see if that helps.