Hey all, I've been having some trouble with my desktop pc, a HP Media Center m7640n. It started a few months ago, where I would turn on the computer, all the fans would start running(On high), the lights on the keyboard and mouse would flash once, dvd drive would cycle, and then the computer would just sit there. No signal to the monitor. If I powered it down, and unplugged it for a few minutes, it would then start when I plugged it back in. When it was running, it ran fine, no problems. Yesterday, It froze up on me, so I had to shut it down. I could not get it to start at all. I opened it up, blew out the dust, checked all the connections, and then tried to start it while open. It started. I then shut it down, closed it up, set it back up, and it would not start. Opened it back up, checked all the connections, and tried to start it. It wouldn't start. I have a spare power supply(not new, used), so I put that in. Still wouldn't start. I disconnected everything, and tried starting it with nothing attached to the motherboard(no cards, ram, drives). Wouldn't start. So today, I had it opened up, and I was able to start it twice. I shut it down, closed it up, and was unable to start it at all. Opened it up again, and moved things around, and haven't been able to start it at all. So, untill yesterday, the case of the computer has never been opened. Tried switching power supply's, didn't do anything(unless the used one I tried was defective also) Tried removing devices/ram/drives, to see if that was the problem, wasn't. Any ideas? I'm kinda thinking the motherboard, except that it does occasionally start, and it runs perfectly once booted up.