Hey guys, really hoping someone can help here..... I was watching a film on my pc last night and the computer suddenly turned off. When I tried powering up again it instantly turned off again only just giving the fans chance to spin up. I decided it must be the power supply thinking I was over doing it with all the hard drives (only just added another sata drive couple of days before) so went and replaced the old 350 watts with 400 watts. Had better luck, the computer stays on now but will not boot. I don't get a POST beep even when I take everything out and just run cpu and 1 stick of memory... same thing. Before power on I have a green led on the motherboard. Power up and I have a red one. Any ideas? I am fearing a dead motherboard but really hoping I can fix the problem. Thanks, AJ

if you had the cpu out, check for bent pin

I'm surprised that you would only go for a 50W increase in wattage? I would have gotten a 500W unit. What brand is your new 400W PSU & how much did you pay for it?

You say you just added a new sata drive days before? It is possible that a wire came loose and took a day or two to loose finale connection. Changing out a ps also involves moving alot of wires and cables around. I would go through and check all connections including the ram. Actually unplug and reconnect...not just push and wiggle. If the original ps went out it is possible one of the leads got underpowered ...computer shuts down or over powered.....stuff fries. Hope it is just a loose connection. W.L.

Pull the RAM and see if you get any error beeps. If you don't then the old power supply probably took out the motherboard when it went.