Random computer shutdown

[Technochicken]

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I build my computer about six months ago. The other day, I turned on my computer, and as windows was loading, the power cut off. I thought it was just a temporary power outage, so i tried to reboot. during the post, before windows started booting, the power cut off again. it has been doing this since then. If i wait a while before i try to boot again, it will get farther before it turns off, and if i power on over and over, it takes less time to turn off every go. I run vista with 2gb of ram, PD overclocked to 3.5ghz, a gforce 8500 with 256 mb vram. I have a 500 watt power supply, and it has worked fine for 6 months, so everything should be getting sufficient power. It is plugged into a surge protecter, so the power outage should not have damaged any of the components. I don't think it is overheating either, becasue the mobo's beep code says that everything was working during the post, and usually the fan keeps the cpu at around 40 degrees C. Can someone please tell me what might be wrong, because i have no idea.

 

[larryiam]

well check to see if all fans are spinning. well could be a faulty power supply. if you have a psu laying around, if so, try it.

 

[Technochicken]

all the fans are spinning normally, including the fans on then psu. Unfortunately I only have a 20 pin pau lying around, and my computer uses a 24 pin connecter. If this is any help, the computer makes a kind of quiet buzzing noise before it turns off, and the sound comes from sewhere around the psi or the CPU

 

[larryiam]

well when you start your computer up can you feel any heat coming from the cpu or video card?

 

[Technochicken]

yes, the CPU heatsink heats up, and the computer registers the CPU in the post, if it gets that far before it shuts down. And the video card is working fine. Because the fAn spins, and I can see the computer registering all the parts on the pre-boot loading screen.

 

[Tmagic650]

A bad hard drive? The drives MBR (master boot record) may be corrupted. Can you swap the hard drive or test the suspect hard drive on boot up?

 

[Technochicken]

but a bad hdd would not explain why it would often shut down before it even got to booting from the drive. I mean, sometimes it powers on about a second after I press the power button, that is before the computer even registers that the he'd is there. And when it does get farther, the drive appears as sata device #1, and displays its size and manufacturer. And how would I know if it were corrupted. What exactly does that mean?

 

[Technochicken]

update

so I tested my power supply in an old dell, and it worked fine, so I know that that is not the probem.

 

[Technochicken]

things just got quite a bit worse. I reistalled the psu and now all that happens is the power light comes on and the CPU fan twitches. Everything is plugged in, and I have no doubt that the power supply works. I think it probably is the motherboard. Could someone please confirm this, or give me some other reasonabe explanation!!!!!!

 

[Tucker4321]

It does sound like your motherboard could have died. You have not replaced any parts lately that may be incompatible? RAM for example.

 

[Technochicken]

After spending hours on the phone with the tech supports of various companies, I just gave up and took the computer to a local computer store. I turns out the motherboard was damaged, probably by the power outage that shut down the computer while it was booting. And it took my hard drive along with it. Luckily both are under waranty, so the companies will replace them=) and no, I have not upgraded or replaced anything since I built the system.

 

[Tucker4321]

well as long as the parts are under warrenty so its all good. Hope it all works out for you.