My computer stopped working. I don't know what the problem is.
Symptom: When turning the computer on there is a short movement of the fans (the PSU fan and the two fans that are connected to the motherboard). Then nothing happens. This is repeated as long as the power is on.
I have unplugged all cables and reconnected. I also tested the power supply by shortcutting the 20pin connector with a paper clip. The PSU run OK then but not when the connector is connected to the motherboard.
Is it a Power supply problem? or a motherboard problem? or something else?
I think its your motherboard but please do tell me, have you tried turning on the computer without the graphics card installed? 550 watts looks like enough for your system but if you have a crappy PSU powering the whole thing then thats a dead answer right there.