New PC Build, Turns on and off repeatedly

[KainG]

Hi all,

I recently assembled a new PC, and my main problem is that it keeps turning on and off repeatedly. I would turn it on, the mobo lights up and all my fans start start spinning, but then it would just shut itself off. Then, 2 seconds later, it would turn on then turn off again until I switch off my psu.

What's weird was that it managed to boot up to Windows and ran properly for an hour. I managed to check my cpu temperature and it was running between -40 to -50 C. But if I gave the PC the slightest tap, it would shut off and do the on/off dance again.

I'm reasonably sure that everything is plugged in correctly, and I'm all out of ideas as to what could be the problem. Can anyone help?

Here are my system specs:
Intel D975xbx2 motherboard
Intel Core 2 Quad Q6600 2.4 MHz
eVGA GeForce 8800 GT
OCZ GameXstream 850W psu
2 x 1 G Kingston HyperX PC2-6400 DDR2 RAM
Sound Blaster Audigy 2 sound card
Ultra ATA/133 PCI Adapter card
2 DVD writers
2 hard drives.

Thanks.

[jasonz0rz]

Are you positive your heatsink fan is spinning?

[excuzzzeme]

It sounds to me like the on/off switch being stuck or mis-wired.

[KarmaKiller]

Hi there.
I had a system do something similar to me before, and it ended up being a PSU. The weird thing is it was the same exact PSU you have listed in your specs. So you might want to check that first.
Next thing that sounds weird to me is if your temps were at 45-50 on just a windows desktop screen, I'd say once you hit 80% load, or even less maybe, your getting some pretty high temps. Can you check your temps in BIOS? If so, see what they are.
This could be a overheating CPU causing your problem.

Good luck!

[KainG]

Originally Posted by jasonz0rz

Are you positive your heatsink fan is spinning?

Yup, the heatsink fan is definitely spinning.

[KainG]

Originally Posted by KarmaKiller

Hi there.
I had a system do something similar to me before, and it ended up being a PSU. The weird thing is it was the same exact PSU you have listed in your specs. So you might want to check that first.
Next thing that sounds weird to me is if your temps were at 45-50 on just a windows desktop screen, I'd say once you hit 80% load, or even less maybe, your getting some pretty high temps. Can you check your temps in BIOS? If so, see what they are.
This could be a overheating CPU causing your problem.

Good luck!

When I used SpeedFan to check the temp of my CPU, it listed it at -50 C, not +50 C, so I'm pretty sure that's not the problem.

What was the specific problem with your PSU? Did you have to replace it?

Thanks!

[KarmaKiller]

Hi again.
I ended up sending it back to Mwave,(where I got it from) and RMA'D it. They didn't have any more of those in stock, so they sent me the 600w version, and gave me a credit. Which I'm running the 600w version now, and it works great.
I'm not for sure it's your PSU, you should really get a PSU tester, or swap the PSU out with an extra you might have, or borrow one from your friend or something. I wouldn't send back the PSU unless I'm absolutely positive that's your problem.

EDIT:
For now I would see if you can check your temps in BIOS. See what that says. It sound like a overheating problem to me more then anything.

[KainG]

Hi all,

I finally figured out what was the problem. I tested eeach part of my PC on cardboard to make sure each part was working, and they were, so I deduced that the problem was my case, and it was. I had forgotten to remove a mounting screw that was not being used and that was touching an unprotected part of my mother board. Once I removed it and re-installed everything, everything boots up just fine.

Thanks to everyone who provided suggestions! Thanks especially to Karmakiller who put me on the right track!

[kayfgibbs]

I am having this problem and I just built my computer. Could you be more specific about the mounting screw? I've been told it could be RAM and after doing an internet search I read it could be the blaster worm but I think the blaster just shuts the pc down randomly not on and off.

I've checked the power supply and heatsink and cpu. The power supply tested ok. The CPU and heatsink were mounted to the board by a technician and seem to be mounted correctly. I unplugged everything and then plugged it back in and this did not help. I took the heatsink off and then put it back and then computer booted fine. I then hooked up my DSL and after 15 minutes of being on the internet it started the same thing over again. I bought another stick of RAM to see if that's the problem, as it was suggested to me. Parts:

Intel DG33FB mother board
Core 2 Duo processor 2.0 ghz
DVD RW

[Prince Lalijama]

Kayfgibbs, if you still sign on to techimo, which I'm not sure you do, post your issue in another thread.