PC shuts down, won't turn on - bad PSU?

Built a new desktop system about two months ago, everything's been working fine. Today it shut down immediately and will not turn back on. I left it unplugged for about 20-30 minutes, thought maybe it had overheated. When I pushed the power button the fan LED flashed and the fans spin for about one second, then everything quit. Tried again later. Same thing. Then I unplugged everything inside, took out the CMOS battery, put it back in, reconnected the PSU to the motherboard (but no components) and tried to turn it on. Again, same thing.

It had done this a couple times over the weekend - I mean a dead cold shut down, not the normal way - but it always turned back on. Not any more.

Bad PSU? It's a 700W OCZ ModXStream Pro. Been looking at the OCZ site for info., too. Looks like mine is dead, but wondering if it could be something else?

Unfortunately, I don't have a spare PSU. I had thought about buying a new one, trying it out, then taking it back.

OCZ's site has a jumpstart test, and I hooked the PSU to one hard drive and nothing else, and the hard drive fired up and stayed on. So it sounds like a component problem, not a bad PSU. Two things I did not mention earlier:

Thing 1 - when my PC shut down it was only during playing Modern Warfare 2. At the time I thought it was problem with the game, because it has had issues.

Thing 2 - One time playing MW2 I noticed a pixel static, artifacts, whatever on the screen. They only appeared one time. I rebooted, played the game and they were gone.

Bad video card?

it still can be the PSU since the HDD doesn't use all voltages (only 5 V, I believe). However, also could be the motherboard.

shutting down during playing could be several things:
- insufficient cooling
- too weak PSU (doubt that in your case since you have 700 W)

the artifact could be the same as above plus a simple software error, especially since it didn't re-appear. you might be looking at several issues that are not related.

Well, I tried all the components with the PSU and they all worked except the video card. MicroCenter is about 15 minutes away from me, so I went down there and exchanged the old card for a new one, same kind. Now my system boots and I can look into it in more detail and see if everything is in good order.

One thing I noticed with the new video card - there is no fan on it any more. They replaced it with a huge heatsink. When I opened the box I thought I got the wrong card. Nope - right model. Box was sealed properly, which meant I hadn't gotten someone else's return. Wonder if the manufacturer realized I wasn't the only one with a cooling problem (if that's, in fact, what the problem is/was)?

Appreciate the feedback.

Jiminy freaking Christmas, typing this on my laptop because the desktop just abruptly shut down after about 5 minutes of minimal use. Wasn't killing Russian terrorists in MW2, just working on getting dump files.

do you have a volt-meter to measure the voltage if it is high enough? i don't think that is the problem since your PSU is large, and in idle you wouldn't have problems assuming it worked a while under load. just to exlcude that easy test.

my tip would be mainboard or RAM. Since your system shuts down quickly, there is no testing that with common software. I'm hope someone comes up with a simpe, way of figuring this out short of you buying all new components to trial-and-error which one is the cause.

i assume you already triple-checked all cables etc. so that none is broken