Sudden shutdowns and restarts

[Fede 0]

Hi guys,
I hope you can help me. I've been geting this strange error since I formatted and reinstalled Win7 64. But let me begin from the start.

Back in February I had a windows update which caused my 32bit applications (FSX inclusive) to crash on starting. Firefox, Explorer, FSX and other apps couldn't run anymore. I then found out that reinstalling the video drivers fixed the issue. Until the next system restart...upon rebooting, the problem came back. So basically I had to reinstall the Nvidia drivers each single day.. Format C: and here we go.

I thought I was good. Reinstalled OS and all the updates, the problem showed again. So I reformatted, reinstalled OS and blocked the updates ( I can't understand which is the one causing the issue). Everything's perfect now, but....

every day or two, my PC restarts like somebody pulled the plug. Bang, no BSOD, no errors, nothing. Just everything turns black and restarts. I unflagged the option to restart the system after a crash, but it does restart anyway, it simply doesn't care. It shuts down and restarts in 3 seconds. All BIOS power options are OFF. It shouldn't start on its own if the power goes off. And in fact it doesn't. I tried switching the PSU off manually and turning it on in a second and the PC stays off.

I removed all the dust, temperatures are well under control, I even bought a Watt reader to plug in the wall and my PC under OCCT PSU stress test absorbs 500W. Mine is a 650W Thermaltake toughpower, but it's 5 years old, just out of warranty...
MB drivers are the latest, updated the BIOS, but nothing to do...

Right now I am thinking at two possibilties: PSU or Video card. The PSU for obvious reasons, but I think my video card has something wrong for the first error that I had to format the PC.
Can, in your opinion, be a short circuit triggering a protection? In the PSU or Mobo I mean.
I forgot to tell you that it happens at idle usually, not under stress. Most of times I'm just browsing the internet.

Thanks for your help

Cheers
Fede

[martin-w 3,235]

A while ago, I had similar problems. I suspected all manner of things, both software and hardware.

 

Not only did I reinstall the OS, but I swapped out various components in an attempt to identify the issue.

 

Guess what? Upon testing my PSU with an Antec PSU tester, I noticed scorched pins on an ATX extender cable. I ditched the defective cable and all was well.

 

Just to say, you can suspect software and all manner of hardware... but don't forget to check all cables and connections. You's be surprised how often they are the culprits.

[Fede 0]

Thanks Martin, but cables are ok. I checked everything inside the case a couple of days ago, unplugged and replugged every card/cables etc. Everything looks normal...I'm now changing the Keyboard and Mouse with old school ones cabled after advice of a customer of mine (IT chief), the PSU will come next eventually. I already have one in my ebay (Corsair HX 850), but I'll wait after the weeekend for more testing. I want to check every hardware I have attached before spending 150 euros on a PSU...

Cheers

[martin-w 3,235]

I use this guy to test PSU's, great device...

 

http://store.antec.com/Product/accessories-other/digital-pc-power-tester/0-761345-77204-4.aspx

 

Works great, cheap,and easier than a test meter.