I installed that 9800 Pro in my friend's computer. It black-screened randomly, on Windows start, in games (at launch) etc. We opened the case (it's an HP Pavilion a720n) and put a fan next to it. It run stable now, with the card underclocked to 300 core, 300 mem. What should I buy (keep it CHEAP) to cool this thing down? Underclocking is not an issue, it's great for this person as is.