PC shuts off immediately

[Fctsu2000]

Hi guys.

So i was watching netflix and suddenly my screen went black. The monitor acted as if the computer was going to sleep but the pc was still on. Before i hard booted it i checked to make sure all the exterior cables (to the monitor) were seated properly. After i shut it down manually it will no longer turn on. It will turn on for a split second but immediately turns back off. No beep, just the lights inside the chassis and the fans are on so briefly that they dont even complete a rotation.

I built this rig about 3 years ago. I reseated all internal cables including the ones running from the pwr button to the mobo and the psu to the mobo. I placed the video card in the other slot and changed sata cables around. All this lead to the same result.

Remember i built this 3yrs ago so i may not know exact models but i know brands.
Specs:
Gigabyte mobo
Nvidea gtx 9800 video card
Antec power supply
Primary hdd WD caviar black 500GB
Back up WD caviar green 750GB

I know its not the hdds but i cant eliminate the possibility that its not any or all of the other 3.

Any help would be greatly appreciated!
I can be emailed at fctsu2000@gmail.com

[Rudek]

So the computer turning off and not turning back on after a while *usually* is one of two things.

The Power Supply or the motherboard.

I have seen odd cases where the PS damages the MB in which case, it's both.

Does your computer normally make a beep sound when you power it on? If it does, does it do that now?

I know it sounds stupid, but physically unplugging the machine from the wall can occasionally fix a jammed up power supply. Something to try.

So the next thing to try is replacing the power supply (Why? Because it's cheaper and easier than replacing the MB).

All you really need to do is get another power supply, making sure that it's as least as good as the one you have now in terms of Watts, and matches either the 20 or 24 pin (altho some connectors have a snap on for going from 20 to 24).

So connect the 20 or 24 pin motherboard connector, and there should also be a connector with 2 yellow and 2 black wires in a 2X2 configuration somewhere near the CPU (usually). There should already be a connector to it from your old MB.

Make sure you connect a power source to the new Power supply and see if the machine boots.

If it does, you know, if it doesn't, you know.