Random Power down on newly built machine

[superhalo]

I built a computer from scratch and I'm encountering a strange problem. I am running an AMD Athelon II, 4GB RAM, 500 GB Hard Drive, 430W power supply (more than enough power). I built the computer, installed Windows 7 and got most of my programs installed, but now it is powering down randomly. This happens in Windows 7 and sometimes immediately after POST. It's not displaying any prompts before, just powering off. I thought the power supply was bad so I bought a new one and it is still doing the same thing. I don' think it's overheating because I got a utility to monitor temperature and it is around 23 C. I also removed the video card and switched to the integrated video to reduce the amount of power being drawn. It doesn't beep before powering down it just shuts off. Does anyone have any suggestions? I've put a lot of money and time into this and I really need a working desktop computer.

 

[wintermint]

Where did you purchase your parts? How was it delivered? What brand is your power supply? Return the power supplies you bought/RMA to the manufacturer for replacement. You should really buy quality power supplies from reputable sites/retailers. That way you know your product wasn't mishandled. The usual quality brand that's budget friendly is Antec and XFX. Corsair and Seasonic are more on the pricey side. Anything from Seasonic is pretty much gold, they manufacture for xfx, antec, and cosair, and themselves of course. Don't end up paying for the fail power supplies. Get your problem(s) fixed now.

Here's a good power supply: Antec Earthwatts 380W $47 after shipping
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371033

 

[Awesomesquared]

Did you use Mobo standoffs when installingthe motheboard?

 

[superhalo]

I bought the parts from newegg, except for the second power supply. I got that from best buy. They seem like quality parts.

As for the standoffs, the motherboard didn't come with any. I'm basically stripping an old machine and putting in new parts to make this build, so I re-used the screws that were in the old motherboard.

This problem is really strange. Sometimes it goes about an hour then shuts off, others it starts to post then shuts off. I didn't apply any extra thermal paste, other than what was on the retail heat sink and fan.

 

[finn281175]

I would reconnect everything outside the case and see if the problem still occurs. If it doesnt then it could be that something is shorting inside the case.

 

[RogueKitsune]

I would unplug all case fans front-side usb/audio and see if it still does it. I have a couple friends that had similar problems. One was having random shut-off mostly during POST that was caused by a faulty wire for a case fan. The other guy had a Cooler Master case that had a short in the front-side USB that would cause his system to randomly shutdown(Seemed to be a common problem for that particular case model).

 

[tsnor]

Hi,

"I built the computer, installed Windows 7 and got most of my programs installed, but now it is powering down randomly. This happens in Windows 7 and sometimes immediately after POST."

Just to rule out software problems, boot to the bios and let it set there. Do not let it boot to windows.

If it powers off while sitting in the biso then its hardware. Use Finn's suggestion "I would reconnect everything outside the case and see if the problem still occurs."

If it won't power off then boot fromt eh windows install CD, let it sit for awhile, verify it doesn't fail, then reinstall windows, don't load anything else, don't connect to network, and see if its stable. Win7 can pull the power and will if it thinks that data corruption will results with continued processing.