computer shutting down

[johnnyhildo]

Hey guys, I've been having computer troubles - my computer was running fine earlier today, but then Windows Vista decided to shut down my computer (i.e. it was just a normal shutdown, but not initiated by me). Now, every time I try to power on the computer I can hear it power on for 1-2 seconds at most, and then it shuts back down.

System specs:
Q6600 (G0)
GA-P35-DS3P
eVGA GeForce 8800 GTS
Crucial Ballistix 2x1GB DDR2 800
Corsair 620HX


I have already tried re-applying the thermal paste on the CPU, just in case that was the problem. Also, I tried resetting the CMOS with a screwdriver (I am assuming I did this right, however). But still, no luck.

It seems that the power supply might be the next thing to check. I just wanted to see if you guys think I missed a step or anything obvious that I just simply overlooked.

BTW: I built the system myself over a year ago and it has worked fine until now.

Any help would be greatly appreciated. Thanks!

 

[4thSurvivor]

Correct me if I'm wrong but if the PSU were dead/at fault, the computer wouldn't power on would it?

You have a nice rig, and I'm sorry to hear that you're having these problems...
I used to run Vista Ultimate on my rig, and it would do the shut downs as well not initiated by me, but it would always turn back on...and I eventually uninstalled to XP Pro SP2 because of compatiblity issues w/ my current mobo, and Vista...have you google'd around, or tried anything else?

When you "reset" the CMOS you mean you took the battery out, unplugged the power supply from the pc, let it sit for a min, reconnected it all?

 

[daniel49]

may be a safety thing in the psu. try shutting off psu switch for 10 secs then back on.
Does the cpu fan spin on in that 1-2 seconds?
any smell or unusual oder?

 

[johnnyhildo]

Hey guys.

I've heard of bad PSUs causing problems similar to the ones that I am experiencing. The automated shutdown is weird, but I think it's interesting only insofar as it might help diagnose my current hardware problem (maybe the CPU was running too hot, so the computer shut itself down). For resetting the CMOS, I just used a screwdriver to jump the reset connectors next to the battery (I made contact for about 5-10 seconds). I could also try to take the battery out for a minute.

The fans all spin on for the short period that there is power, but I don't smell anything unusual. My best guess was a CPU heating problem, but I already tried resetting the heatsink. It's probably worth mentioning that I was running a mild overclock on the CPU (3.0 ghz I think), but that was never a problem before. I checked the temperatures frequently after overclocking and they were all in a safe range.

I'm just hoping it's not a motherboard or CPU problem because I have no easy way to eliminate those as possibilities.

Thanks for the quick replies!

 

[Harvey]

It could be a problem with your PSU's self protection circuitry, or it could be a condition on your motherboard, vid card or any other components that draws significant after it warms up under power.

It may be something easy to exchange, such as a stick of RAM or your vid card. Start by unplugging everything not needed to boot, including your CD/DVD drive, and remove all but one stick of RAM. If it boots, you'll know more. If not, try a different stick of RAM or a different vid card.

If you can't find a problem in the setup, try your PSU on another system and/or another PSU on yours.

Good luck.

 

[Laputa]

Or could be the power-on switch got stuck or going bad. You can remove the power on switch cable and try to hot jump it for a second to power it on. If there's a reset switch, you can swap that if that's the issue.