My Computer Specs are the Follow:
Power Supply: OCZ GameXStream (700W) OCZ700GXSSLI ATX12V Power Supply 100 - 240 V
Motherboard: Asus M2N-SLI Deluxe Socket AM2 NVIDIA nForce 570 SLI MCP ATX
Memory: CORSAIR XMS2 2GB (2 x 1GB) 240-PIN DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit
CPU: AMD Athlon 64 X2 5200+ Windsor 2.6GHz 2 x 1MB L2 Cache Socket AM2 Processor
Video: eVGA Geforce 8800 GTS 320 MB

When I turn on the computer, it turns on for 3 seconds then it shuts down automatically. I don't have a chance to see anything on the screen. This morning the computer turned on just fine, and it shut down just fine. I never had a hardware problem. The computer is brand new, I built it this year in May.

No sound happens during this 3 second period. All fans turn on just fine, even the power supply one.

I troubleshot by disconnecting just about everything from the power supply like hard drive, cd-rom, video card.

Is there anything else I can do before taking the power supply and test it in another computer? I posted on this forum because I think the power supply is the problem, it could be the motherboard also I suppose.
Thanks in advance ^^

Try removing the case power switch and CAREFULLY shorting the pins on the mobo header, that will rule out a bad switch. You could have a short somewhere that reared it's ugly head. Try building a minimum system on a piece of cardboard. If you have access to a PSU it would be easier to swap the psu to test.

Edit: If you are going to swap PSUs, don't test yours in another computer, test another one in your computer.

are you overclocking?

last time this happened to me it was a bad cpu

I am not overclocking,

That shorting the pins thing sounds kinda scary, I think I'll test my PSU elsewhere or get a PSU from someone and test it on mine computer.

Thanks for the replies, I would reply once I know what the problem was for future reference.

I second what Zorg offered. Test your system with another PSU (borrowed or whatever) and if that doesn't change anything, than I'd pull your stuff out of the case and test it on a piece of cardboard. This will rule out any possible shorts that your getting from the case.

ok, I grabbed another PSU (300W) and it worked. What if that PSU doesn't have the technology that detects a short?

It should, its probably a bad PSU. Try putting it in another computer to test it, or get a PSU tester.

Edit: Or just send it back.

I don't get it.

When I said that I tried another PSU and the computer turned on just fine, I tried it with the other PSU outside the case, that's how it turned on. But when I put it inside, it shut off after 3 seconds just like the other one.

I just put the motherboard naked on a cardboard, same with the 1st PSU on a cardboard. It shuts off after 3 seconds with boths PSU's. The way I turned on was with the cables from the case connected to the motherboard, I don't know other methods.

Please help me, why the computer turned on that one time? What is causing it?

I guess I can't overuled a short since I still grabbed the cables from the case and connected it to the motherboard then I turned it on like I normally do. The case looks fine.

I am gonna take pictures and post it.

Sounds like you have a short on one of your connections, probably the power button or the reset button on the mobo. You might want to double check them and see if they are shorting out. It's possible that you might've plugged them in wrong on the mobo and thus you get the short. Just double check all of your connections that go to the front panel.

I just did, I double checked with the manual and everything. Could the short be coming from the case?

The only thing I have connected is the power supply (of course), the CPU, and the Front Panel Connectors, thats it. Both fans (PSU, CPU) turn on for 3 seconds.

You missed one of the reasons for building outside of the case, which is removing all connections to the case. remove all case connections and short the power switch pins with a paper clip or screw driver as I said earlier. there is no real power on those pins it's just ground sensing. It's not dangerous, just touch the two pins together momentarily. If the mobo still resets with both PSUs, then remove the VGA to rule it out. It should beep but stay on. If not try removing the RAM, same thing. Post the results.

Yes you could be having a short from the case. I'd look at your front panel wires and where they are going. You might have an internal short from your power or reset button. Pull them off the mobo and do what Zorg suggested with regards to shorting the connections.

Zorg, what about insulating the mainboard from the surroundings, say with some rubber plates fixed on the screws??
Can I skip the step of removing all the connections without bicho33's problem?
I know that I ought to follow the instructions, but I am curious about the effect of the insulation recommended by my friend.

Hey Zorg, you are gonna have to be more specific, english is my 2nd language.

Let me see if I understood what you said:
Take all connections that are coming from the case out of the motherboard. Use the screwdriver to turn on the computer by touching the pins that are suppose to be coming from the case cables, right?

Do I do this while the PSU is on? The intention here is to turn on the computer without using the case cables to ruled out a short coming from the case, right?

I am scared of electricity. I get shocked every time I open any car's door.

Is this bad?



When I built the computer it came out with 3 standoff screws, I put those on the third column because the third column looked lowered. The rest are just normal screws from the motherboard to the case. I didn't use anything else.
So, 9 holes, 3 were standoff on the third column, 1st and 2nd column are normal screws that came with the motherboard.

You can't get shocked from 12V. Yes, remove all of the connectors from the case and temporarily short only the 2 pins that go to the power button. Check the manual for the correct pins. Obviously the switch on the back of the PSU would have to be turned on, if it's not then you will never be able to power the mobo.

I can't see what is going on in that picture. I don't know of any mobos that would use standoffs for some screws and not others. Give me a link to the case and let me check it out.

Do you have a shorting problem, or do you just want to be extra careful? If so what are your symptoms? If you are using standoffs you don't need any plastic washers (plates).

My case is labeled as: AeroCool ExtremEngine 3T - Twin Turbine Technology.
http://www.aerocool.com.tw/case/3t/3t.html

I'll try the screwdriver thin and post results.

Ok, I finally did it. The computer turns on and shuts down after 3 seconds when I touch the mobo headers with the screwdriver. This time I tried without a memory stick and without video card. I tried with 2 PSU's.

This probably means that the motherboard is dead and that I need to replaced it?

The fact that I only used 3 standoff screws might've something to do with it.

Is this in the case or on a piece of cardboard? If that is in the case then take it out and try on cardboard. I haven't looked at your case yet let me do that. If it doesn't run on the cardboard with the case completely disconnected then it could have been damaged from shorting to the case, or just died on it's own. It's also possible that it is the CPU.