Hey Guys,

I'm having a large problem with my desktop computer. It won't boot at all. It'll turn on, I'll get the fans spinning up, (Power supply, Processor, Case and Video Card) The front power light turns on for three seconds then turns off. In order to repeat this process I need to unplug the computer and then wait until the green light on the power-supply turns off. Then plug it back in.

Here is what I've done so far:

1.) Reseated all RAM
2.) Reseated the Video Card and other expansion cards.
3.) Reseated all cables, and switched out HD's.
4.) Removed Video Card, all but one stick of RAM, Hard Drive and all other expansion cards.
5.) Verified that there were no wires touching the motherboard.
6.) Verified that the connections to the power button were working.
7.) had start-up disk in the CD/DVD drive.
8.) disconnected the CD/DVD drive.
9.) Replaced motherboard battery
10.) Flashed CMOS.

Beyond that I'm not sure what the problem could be. At first I thought it might be the power-supply but the greet light is on, which means it's working. I'm not even getting to the POST test.

I'm really not sure what to do from here.

 

Power supply could be pooched, It might run for a second before its start over loading. Or there is the possibility that something else in the box is shorting out. Off the top of my head i can't think of anything else that would shut the computer down after only 3 seconds.

I have seen situations where the green light stays on regardless or it working properly or not. It usually just means that the box is getting power in.



To see if this is the problem I would recommend using an old power supply to see if the computer boots with it.

 

Does your mobo have any burnt spots on it?

 

Sounds like a PSU issue. Or, like me, one of your expansion cards could be fried. If it doesnt boot with all of them removed, though, its not that.

Try a backup powersupply.

 

The mobo looks completely fine under visual inspection. I'm going to switch out the PS tonight and see if that helps. I really hope it does.

 

Most likely either PSU or mobo (my money is on a motherboard problem if your fans and lights come on, but it doesn't POST).

 

I'm thinking motherboard but I have a few questions,

First: What kind of computer are we talking about? Dell, Custom Built, HP, what? Each brand has different things that can cause that.

Second: What motherboard do you have?

Third: What power supply do you have? 500W, 700W, 1000W? A different number?

Fourth: Are there any strange smells coming from anywhere?

Fifth: Are all the jumpers in their right spots on the motherboard?

All right thats it.