I have a Dell Dimension 9150. After a power outage my PC will not turn on. It has a blinking yellow light. Everything I have read said it is most likely a power supply problem. I purchased a new power supply from 911 PC and still have the same problem. There is a green light lit up on the motherboard. Any ideas? I have also read about dianostic lights to figure out the problem. I don't believe this PC has any of those lights. Thanks