HP Pavillion A6430F won't boot at all?

Hi, I have a hp A6430f desktop, phenom x3, vista premium that has been running flawlessly for the last 3 years. I blew off the cooling fins around the processor, the fans, then vacuumed it out which I do on a regular basis. Went to start it up and nothing, won't boot up to anything. I get a couple of flickers on the hard drive light, then nothing. Re-seated the ram, pressed the different connectors figuring I may have knocked something loose. Any ideas where to go from here? There is an indicator light on the back of the tower that is green. Thanks