Sudden Shutdown : My half-informed diagnosis for your edification/amusement

Tom's Hardware is my EMT. I never visit except when something bad has happened. I hope that's okay. Life has taken me away from the ready-knowledge of system builders and troubleshooters.

The Problem

My computer has taken to shutting down during games, especially when things get intense. My system is connected to a heavy PSU that has been happily absorbing my minor Seattle-area brownouts. Click…click. But with this new error, a loud, persistent beep irritatingly coughs its throat. I have to shut down the PSU. Turn it back on. Then boot the computer.

For the past week, I've been google-flailing at the symptoms, wondering if it was my PSU or my video card. Then I realized: There are way smarter people out there who have the benefit of not being me. Hi People! Here are things!

Mobo: Gigabyte GA-MA770T-UD3P (AMD Phenom II X3/X4)
CPU: Athlon II X4 630 @ 2.8 Mhz
RAM: 4 GB (2GBx2) DDR3 (1333Mhz)
Video Card: NVIDIA GeForce GTX 465 (1GB)
PSU: OCZ600MXSP (ModXStream Pro)

Here are some more salient things I've observed. I'll just put them here and you can quietly judge me. If I've neglected a fact, it's because I dismissed it as not important enough (face it, you have other things to read).

Who Doesn't Love Lists?

1. There have been zero cases of a BSOD accompanying a sudden shutdown.
2. I can't seem to track down the appropriate event code number, but there are no driver failures.
3. It has been somewhat hot lately (late summer in Seattle), but not nearly as hot as it was a few months ago and there was only one case of that happening, which I chalked up to heat.
4. My video card (specs below) was purchased and installed (new) not more than four months ago.
5. My PC is a homebuilt system which I've been updating and maintaining for… god, I don't know anymore. A long time. The mobo was spanking new and the shiniest thing out there.
6. My PSU has aged between 1.5 and 2 years.
7. The shrill PSU beep I mentioned at the start. It tells me that some damned thing just stopped drawing power after sucking a whole lot of it.

Possibly, Probably PSU?

These facts, together, indicate to me that this must be a PSU issue. I've excluded a video card error because I'd be waist-deep in BSOD's and there would be tons of driver failures. I thought it couldn't be a heat issue because, as I noted, it's been hotter. I have fans that run just fine, too, though poor ventilation in my area isn't doing me any favors.

My PSU is an OCZ. Durable stuff, by my understanding. However, I'm playing games that tax my system, and have done the occasional video editing. I'm wondering if the thing has just hit an early end of life. It's a 600W. However, when I plug in my stats into two watt-load calculators, I get the following recommended wattage:

Extreme Outervision: 459 watt
NewEgg: 531 watt

That's quite a discrepancy, and all the more confusing since I was able to account for more 'stuff' in the EO calculator. Could I just have a bad PSU? Are the calcs more than detritus?

Feel free to grade me. I'm much more interested in taking the right action than being right. I don't have wads of cash to throw at the problem, so I must purchase with precision.

Many thanks, in advance, for your help.

I'm writing this from my netbook, which aught to tell you how well it's going. Here's what I did: I came home, opened it up, and cleaned everything out with compressed air. I reseated everything except the CPU because the idea of dealing with that little latch scares me.

Then, I powered it up and opened up OneNote to get at my notes. BEEP! No can do. I didn't even make it into SpeedFan and the UPS did its loud beep. So, I powered the UPS off. Turned the PSU off. Turned them both back on.

I booted and very quickly ran SpeedFan and then saved it to DropBox. Here is what it looks like: https://www.dropbox.com/s/0pos3ea4xqscar4/SpeedFan.png

Now I'm stuck using this damned Netbook, which *sucks* quite hard. Research will continue slowly.

Yeah, that was my thought. And yes, the fans are running. All of them. I didn't believe it either so I pulled the side off, booted, and pointed a flashlight at every single fan to make sure there wasn't just a dead one. They were all running.

I'm sure they aren't running full bore or anything, but I can't help but wonder why I would get increased heat all over the place. Oh! Just for the record, I returned to my PC and cleared out a dust bunny from the heat sync. I also released the arm, cleaned the surface of the CPU (and the heatsync) and put some Artic Silver there. I checked to make sure there was no oversilvering, then secured the heat sync/fan back on.

I booted and it was only a red arrow (instead of the fire). But the temp still started climbing. So I shut down. I'm so incredibly hesitant about using the thing. Could I push a box-fan into the open side just so I can use it long enough to troubleshoot? That just sounds like a trailer-parky solution to me.

Also, I will work hard to find out what the hell a cooling pad is. Thanks!

My friends and I think that Temp 3 is garbage. I also uncovered a screengrab from ~1 years ago. I had the same Temp 3 weirdness. Could it be something real that is only now causing problems?

I swapped out my videocard for my old videocard. The PC started cooler, but still warmed.

At the moment, I'm using the old videocard, but am in Windows Safe Mode. I just ran Spybot and am now running ESET. Spybot found a number of alarming things. Clearly, my regularly scheduled scans aren't happening.

My current plan is to run as many analysis/fixing programs I can in safe mode and baby step my way back to my traditional config. Along the way, I might figure out if it's my new video card along with bad things making me run hot or whatever. I'm getting punchy. Wordmaking hard now. I'll post something more complete in the A.M.

As always, thanks to all you readers and commenters.

Also run malwarebytes anti malware.
Becareful with combofix - it is buggy and it can really screw your system.

I am in washington state too and 11:20 PM isn't that late for me