5-yr homebuilt, no POST beeps, shuts off 1 min. later

[snagglypete]

Hello,

My 5-year-old, homebuilt PC was working fine until yesterday morning. I press the power: computer turns on, fans all working, but no POST beeps and no display. After 30 secs to 1 minute, it shuts off.

Here's what I've done: I took the mobo and PSU out of the case. I disconnected and removed everything from the mobo. I then connected only the following to the mobo: the CPU and heatsink/fan, one stick of RAM, the graphics card, and the tiny case speaker (to hear the POST beeps). I connected the PSU to the mobo and graphics card. I attached a monitor to the graphics card. I shorted the power pins with a screwdriver to turn on the PC.

Here's what happened: the PC powered up and all fans came on (CPU fan, graphics card fan, PSU fan). I heard no POST beeps and no display came up on the monitor. After about 1 minute, the PC shut itself off.

After this, I did the same thing with all RAM and/or the graphic card removed as well. I never heard any POST beeps in any of these tests, but interestingly I found that with the graphics card removed, the PC did not shut itself off.

I also tried resetting the CMOS with no apparent effect.

Unfortunately I don't have any compatible computer parts lying around that I could swap in or out to diagnose the problem further.

Any idea what's wrong or what I should do next? Thanks for any help provided.

Here are my specs:

MSI P6N SLI mobo
Intel core 2 duo CPU
Mushkin RAM
OCZ PSU 700 watts
EVGA Nvidia 8800 GTS vid card

 

[farrengottu]

i had the same motherboard and it gave me troubles. the north bridge got so hot on it that it would do restarts during gaming. and that was a common problem for the board. i betting that yours went the other route and just died. but thats only a guess.

if you know some geeks, see if they will let you swap parts with one of their old computers to isolate the problem. or you could go to a computer repair shop and they can do it for you... for a price im sure.