Hey im making my friends computer, he bought the Antec P180 Case (the one with seperate power supply and motherboard bays) and unfortunately the poower supply is installed on the bottom of the case, and the cables for the ATX 4 and 20 pins werent long enough so he had to get extension wires. Anyway, once i used the wires the green light on the motherboard light up and everything. Motherboard (Asus K8N) is brand new, motherboard is a couple weeks old, and everything else works for sure. So basically it wouldnt turn on, and so I thought it was the extension wires. I tested it by taking the motherboard out of the case and using the real ATX wires and it turned out to be the 4 pin ATX extension. But when the computer DOES turn on it makes the loudest post noise ever. It goes on until you turn the computer off. I havent tried seeing whats on the screen, cus i havent plugged one in to it. If somebody can tell me why its make this loud annoying ass noise please tell me, i need an answer within the hour so that would be great. thanks.
I checked the case model on Antec's website, doesnt look like it comes with a power supply. They do however reccommend power supplies from their Phantom, Neo or TruePower series. What power supply make and model do you have?
More than likely you either dont have the memory or video card seated correctly.