I wouldn't expect the power supply to last long in that case. especially being a 450w for only 29 bucks. it probably doesn't weigh anything. And if you plan on taking the motherboard out of the HP and putting it in the new case, then I doubt if the case wires will fit the motherboard without modifying the wires, but i could be wrong. Thats the problem about buying proprietory name computers such as dell, hp, compaq and others. its hard to change things in them.