I am trying to make an old HP Pavillion work. It came supplied with a 100w PSU, which I suspect has blown out. I will be running a Celeron processor, one HD, a 56k modem card, and one CD-RW. I see a lot of 200w PSU's on Ebay. Do I have to match wattage with the old one, or can I go higher? Before you say that I should junk it all, I have to tell you that I'd LOVE to, except that I promised this box to someone who has no computer.