I'm building a PC and got a problem with a startup thing. I looked through the case to see if there was any plugs I hadn't plugged in. I found one that was going into the hardrive. I plugged it in and rebooted it. But the Computer didn't turn on... I Unplugged it but it won't turn on. I've let the PSU cool for an hour because I read it on another thread, but it still isn't coming on.
disconect everything, use only 1 ram module, do the fans spin? you should get to bios, any beeps? also try the paper clip method to check PSU, basically you put a paperclip on the green and any black wires disconnect from motherboard and connect 1 fan to psu, if fan turns on and stays on PSU is good if not, psu problem