Windows 7: Sudden restart without warning, no BSOD, no power for several minutes

Hello

I've had two sudden restarts in the past week. The first time my screen went black, but the indicator light was still on my monitor, and my computer was still running. Sound was still coming through normally. However my fans picked up speed like crazy. I've never heard them that loud. I finally shut it off manually, and it started back up fine.

Now just a few minutes ago my computer shut off completely. It would not power back on for several minutes, even when I pressed the power button. I opened up my case to make sure nothing had come loose. Also I unplugged my PSU and plugged it back in. Afterwards it started up normally.

The only recent change I have made is an update for my NVIDIA GeForce GTX 670. It was only a day afterwards that the first error occurred.

12/14 I tried to turn on my computer after putting it on standby last night, but it would not start. All I could hear was the fans running. I had to turn it off manually and turn it back on for it to resume.

Any ideas?

Hello.

Maybe high temperatures are causing this issue;check your temperatures with some software,like HWMonitor.

I would also check voltages,just to make sure you're getting enough volts (with HWiNFO).
You can download it here: HWiNFO, HWiNFO32/64 - Download ,64 bit version.
Open it and click on sensors.Scroll down until you find voltages.


Report back here.

Here are the screenshots

Voltages and idle temps are fine.
After reading your first post better,something caused graphics card to stop working hence gpu fans sped up.When computer is booting do you hear that same fan loudness?

Just to make sure:
Have you checked all motherboard connections (24 pin power connection,gpu power connection,etc)?
Run Windows memory diagnostic ;check for RAM errors.
Run SFC /SCANNOW

PS
What power supply are you using?

No, I've never heard my fans spin that quickly, which is what initially concerned me.

I gave an overlook and everything looks fine. Anything accessible I made sure was fit properly. Nothing was loose.

HX650

Hmm.
That's good and quality power supply I highly doubt it's the cause of your issue.
Check for RAM errors and use command from my last post in CMD.

Okay time for much more info:
Were graphics card fans spinning fast?
Also did screen turn black while you were gaming?
Can you write graphics card temp,no need to take screenshot again(it's not visible on original screenshot).
Did you overclocked your cpu or gpu recently?
Updated any driver (except video),bios?

Roll back to old drivers,graphics card is most likely the issue - driver related problem.

Sorry from going to unlikely to likely cause of your issue (I like to check everything and have all info - a bit ocd).

It didn't find anything

Yeah,as I expected.
Like I've said,install older graphics card driver.

I was working on my reply before I saw the rest of the info you asked for.

When the screen turned black, the graphics card fans spun really quickly. I believe that was the only fan making that noise, since my PSU would of been louder, and it was multiple fans spinning at once, which only my graphic card has.

I wasn't gaming when it turned black. I was watching YouTube.

I've never overclocked.

That's last update I had was about a week or so ago, and that was Windows.

How do I roll back the driver?

Don't worry about it. Being in depth in this case is a good thing.

That temp is perfect.
You can go here :NVIDIA Driver Downloads - Advanced Search and search for an earlier version of drivers and when installing I recommend you use Clean install option.