Have you tried resetting the surge protector? Is your monitor plugged into the surge protector? is it showing power?
Sometimes OEM computers like Gateways have their powersupplies made special, so you can't go out and buy one yourself. The best way to tell is to compair the two supplies and the order and color of the wiring. If the colored wires are not identical between the main 20-24pin plug on the one you bought and the one you took out, then the supply may be proprietary. If they are identical and you do have power at the wall then you might try putting in a new stick of memory in one, or doing the old cmos reset by removing the motherboard battery for an hour or so and moving the cmos reset jumper to reset and back to run if you can find it (usually close to the battery). Do all this with the system unplugged from the wall of course.