A friend of mine from out of town called and said that his computer will not turn on. I have no idea how to troubleshoot this over the phone. I am thinking power supply. He says it's a gateway but is not sure what model, it's about 3 years old. Question is do Gateways use a proprietary PSU or can he buy a new one at the store and replace it? I dont want to suggest that and have him fry anything. Thanks.