Computer flashes on then shuts off

[Amidget]

I was playing a game on my pc earlier when it just shut off, like blowing amuse or losing power. No BSOD or error just powered off. When i tried to turn it back on nothing happened. Turned the psu off and unplugged it for 20 seconds or so. Plugged it back in and flipped switch on. The motherboard I have has a power switch that lights up green directly on it. That light turned on when i flipped the psu on. Tried hitting the button and nothing happened. Couple more pushes on the pc turned on for amsplit second then shut down leavin the mouse light on (it glows) and the gaming pad on (also glows). After fiddling with some wires assuming something over heated or shorted i finally moved the 24 pin psu to motherboard connector around. The computer briefly turned on again and shut off with certain movements. Eventually I pulled out the 8 pin 12v atx plug that powers the processor. Oddly enough the pc will power up and continue running. Obviously it won't boot because the processor has no power though. Plugging the 12v back in will cause the pc to shut off immediately after the power switch is hit. I also cant attempt to turn it back on once it turns off without flipping the power switch and waiting for the psu to discharge. The pc is about 2 years old. Built for gaming and has a 1000w psu so it isn't a lack of power or a failed psu because it will start up and stay running withOut the 12v atx plugged in. Which leads me to believe something shorted. I'm just not sure what. The case is acrylic so its not the Mobo touhing metal either. I don't think system specs really matter for This situation and I'm typing this from my iPhone so for now I'll leave those out but I'll post them if needed. Sorry for any misspelling and Ty for and help in advance. Really appreciate.

 

[thundahawk]

Mine does something similar...it turns on for a split second then instantly powers down. Its an older custom machine. Was working fine one second then i go to turn it on and no go for this hobo. The power supply works ( i took it out and got it checked out at the shop). When i put the power supply supply back in it started to run for awhile but with no output to screen. I shut it down then to check the monitor and it never came back... same old problems. Ive tried almost everything. Please help.

 

[T_T]

Have either of you checked the troubleshooting guide we have posted on this forum? If you haven't, please click on the link in my signature. Ruling out these steps will help in diagnosing the problem.