I've been googling this for most of the latter half of today and I realize this is a common event. After the troubleshooting I've done I'm holding out some hope that the mobo isn't trashed, but we'll see... mobo: Gigbyte GA-K8NE Rev. 1001 cpu: AMD Sempron 3100+ RAM: 2 sticks of OCZ 512MB vid card: nVidia 6600 psu: Antec TPII 430 The tower is my #2 pc; my file sharing and browsing-while-gaming computer. It normally runs 24/7. Earlier this afternoon I decided to shut it down and clean it. I did just that, and the cleaning was unremarkable. I removed only the cpu fan, heatsink and then the video card. There wasn't as much dust as I'd feared and it was short work. A few q-tips looked after the rest of the guts of the tower. Cleaned the cpu and put fresh grease on it, put everything back together and tried to power it up. Almost nothing happened. The DVD-RW drive light would quickly flash twice and I could hear the fans just beginning spin, like they'd gotten a half-second of power. Checked the plugs on the back of the tower, tried again a few more times and then pulled it all out and started over again. Checked all the connectors in the tower and they seemed fine. Returned the tower and reconnected it and nothing. Pulled the tower and checked it again. Still seemed fine. Reconnected it and she fired up, but no POST. The fans come on and I can hear the HDDs spin up and run. The HDD light comes on and stays on. But the monitor never gets a signal. The tower doesn't have a speaker and the mobo doesn't have a power light. I haven't been able to get any further than that. There is one thing that I didn't see mentioned in my Googling. Both computer are connected to a DI-604 router. PC #2 is connected to port #2 on the router, and that port's light is always on whether PC #2 itself is on or off. Since this problem started that light has been off. Between my earlier 'progression' in restoring power and this clue that the ethernet port is not seeing power, I'm hopeful that a solution remains. I don't recall bumping anything inside the tower, I certainly didn't drop any tools or anything else onto the mobo while working over it and a multimeter test of the 24-pin power connector said everything was fine. I'm now in the midst of trying power-ons while swapping the RAM around, but I'm expecting that until that light comes on on the router I shouldn't expect anything. Any comments/suggestion would be appreciated.