So, been playing FNV the past week, and literally every time i play, it makes my entire computer just shut off. Now, i have had this happen before, but i've ALWAYS been able to fix it. When it was happening in Day of Defeat: Source, i checked my CPU and it was stuffed with dust, cleaned it out, worked fine after that. When it was happening for some other game i can't think of, it was because my case was old and not cooling my computer off enough. This is not the case anymore, I have a good case now, as well as a radeon 5870, i should have no problem running this game, and even on ultra high, i rarely lag! My computer just...shuts off. Now, i'm not sure if New Vegas is that much more advance compared to fallout 3, but i can run fallout 3 fine and dandy, i can run anything fine and dandy, just seems to be New Vegas that is the culprit. I checked my cpu, cleaned it dry, still happened. Checked my gpu to see if it was getting a little hot, and it was, but i upped the fan and not it stays around 50 degrees celcius, i've tried aiming a powerful fan right at my computer with the side of the case taken off, no bones. I don't know what else to do, i mean, the only thing i could possibly think of is it is the power supply, but if it were, i would be shutting down like crazy in crysis or similarly power hungry games...just don't understand it. Any help, anyone else having this problem? Really makes no sense since Fallout 3 works perfectly besides a few minor crashes here and there, barely looks like they improved the engine and overall look at all! Forgot to mention, this is happening at all low settings, hdr turned off as well, no way that should be happening. Any help would be greatly appreciated!

I also tried updating my video card drivers, no beans!

Have not installed the patches though, will update when i do that, chances are though, this will continue :\.

Might be your Psu is getting hot and has a bad Cap in it. It happened to me, my Psu about a year ago, it developed a bad cap and when it got hot, power was lost and my system would shut down cold.

did you upgrade to that video card? If so you mighen have a powerful enough PSU to support it, card doesnt get the juice it needs and fails causing the system to shut off....

Usually if your pc just shuts off it's the cpu overheating.

Traditionally this has always been true.
But modern CPUs all self-throttle and they are almost impossible to roast...
I would look first at CCC settings (even just the taskbar icon settings, without opening the main CCC).
Ensure all high-performance settings, and no forced AA, AF or vsync.
Then make sure no AA, AF or vsync within game settings.
Also, your system memory can cause crashing such as this.
But you say your rig is normally solid, plays Crysis etc?
The quality of power, and also quantity, produced by your PSU are okay?
Sometimes the motherboard voltages and onboard power are insufficient for rampant overclocking?
But I dunno how you're set up...
Post DXdiag and the guys here will take a look.
Pretty strange (and unfortunate) problem,
Regards

+1 Also may be a cap on the Motherboard. Run Orthos or Prime95 and see if your system stays stable without errors. Then try to run Furmark and see if it's stable. I would only run Furmark for a few minutes tho, it's relatively hard on some problematic video cards like the 8800GTX and the GTX 280's.

If you crash or get errors with Orthos/Prime95 it's either MEM/MB possible but not very likely CPU
If you Crash with Furmark then it's PSU or possibly the vid card

This assumes you have a relatively high end system. Maybe post a DX diag?

There are two things modern CPU and motherboards do to prevent heat damage. The first is throttling when demand on the CPU is low. When playing a game this is not usually the case and, depending on your OS and BiOS settings, throttling my even be disabled when running certain programs. The second thing they do is to shut off when a critical temperature is reached. This sounds like what is happening and mirrors the experience the OP stated he had with a previous game.

As the system has already had overheating issues in the past, this is the most likely problem. It is also possible that the motherboard or the CPU socket was structurally damaged during past overheating. I'm not suggesting serious damage, simply slight warping of one or more plastic components. When the temperature of these components rises enough, one or more connections may be disrupted. This would cause an immediate shut-down without the alarm or warning message that is normally supposed to precede processor overheat. My suspicion is that this is the problem in his case.

This does not mean that anything needs to be replaced, but in addition to a thorough dusting it might behoove him to re-apply thermal grease (I'd go for something like arctic silver) and remount the heat-sink. It might even be a good idea to buy a better CPU fan and heat-sink. Another option would be a more powerful case fan or, if there are spaces, simply an additional case fan. It's always a good idea to make sure that air-flow around the computer is unimpeded and there is enough clearance to get good circulation. If the area around the computer gets very warm very quickly while playing, this is a good sign that heat is not properly being removed from the area. Heck a floor fan right next to the computer can help or simply moving it out from under the desk to next to it and half a foot away from walls and furniture. Space=better heat removal.

No. They will not reach a critical temperature; they throttle.
I'm not talking about SpeedStep (or Cool&Quiet).
All CPUs have critical temps that initiate slowdown throttling.
It's independant of motherboard and BIOS, and cannot be disabled.
New rigs will not reboot (even if you stop their cooler fans).
They keep running windows - but with an immediately noticable power hit!
L8R

He never really told us his specs

Actually some mainboards have a shutdown temp, when the cpu reaches a predefined temp the mainboard will shut the system down, this however is usually after it's throttled the systems back. I get quite a few D3LLs in the shop with broken socket 468 CPU retainers that sut down after about 2 minutes of use with no apparent throttling. I have not seen a more modern Intel or AMD processor do this however.

I should have been more specific- the auto-shutdown is a feature of some motherboards+BIOS settings. It is not a feature of the processor and is wholly independant of the processor. It can be caused by-

High Case Temperature
High Memory Temperature
High Bridge Temperature
High HDD Temperature
High CPU Temp (less likely on newest models as you said)

The exact behavior of this feature varies with motherboard and BIOS settings, as does whether or not it is present at all. It is wholly independant of the chip's behavior and depending on which temperature value triggers it can also be wholly independent of the CPU temp.

Also, some motherboards will automatically power the system off if the CPU fan shorts or loses power. As they have air-blasted their fan before because it was clogged with dust (this also suggests it might not be the newest of rigs) it is possible that the fan bearing is starting to fall apart. A failing bearing in the fan can cause it to jam (which is a short cicuit) at higher RPMs and will eventually lead to the fan failing altogether. This is usually preceded by the fan becoming very loud during operation though. Back in college when I used to repair student laptops, fan failure was a common cause of sudden shutdowns among ThinkPad users. It is also not limited to one brand.

I've checked my cpu after a crash, and it is never hot, fairly cool for being overclocked actually, the only thing that is warm is the video card, and after i fixed ATI's [censored] default that was making it get pretty damn hot(now only goes to 52-53 degrees celcius maximum), my computer is running fairly cool. I really don't think it is overheating, because if it was, i would be crashing like crazy in crysis(not warhead). I'm assuming it is the PSU, has to be, i have really good airflow in my case(i have the haf 932, with an extra fan in the case), i've even tried putting a powerful fan next to the computer on multiple occasions, close, farther away, medium, and it ALWAYS crashes. After applying the patches the game seemingly ran better, and i got a good half hour in before it crashed again this time, before it was doing it at 5-10 minute intervals. I think i may try getting a new PSU, if that doesn't work, it is definitely a temp. problem, which is odd considering nothing really even gets that hot...but oh well... Thanks for all the replies guys, very helpful community full of great people here! Will definitely try the suggestions provided is new PSU doesn't work.

Shouldn't you try to verify the PSU is the problem before you just start replacing it? I agree that it's likely your PSU, however just replacing it without knowing is a $100 gamble... If you are buying an el cheapo PSU you will still have problems, if not now then later on. I personally use Corsair PSU's In my gaming machines, and FSP psu's in business machines.

YMMV

Have you tried running the game, without the CPU being overclocked?

Well, considering i have no problems in any other games, no. I highly doubt this has anything to do with the cpu, it literally happened before because there was so much dust in the heatsink that it got caught under the fan and stopped moving, now i clean it fairly regularly, really doubt it is the cpu.

The thermal compound could had been cooked and needs to be changed out due to it overheating due to your fan stopping, once that happens the tim heats up/bakes and transfers less and less heat, also an over tightened heatsink and a bad power supply can cause your issue. Run something like the new heaven benchmark or metro 2033 to see if you can reproduce it. between that game and that benchmark app it should trigger it.

Well, i can always return it, if the problem persists i would just return it, pretty no hassle.