Need tech support: Computer reboots with no warning or error while gaming.

[Hateren47]

All this talk off PSU's is getting silly. It's obviously a software problem when Windows decides to restart by it self. If it would just cut the power and restart it could be the PSU but OPs computer doesn't do that. I think you have some malware in there. If Malwarebytes Anti-Malware, Spybot - Search & Destroy and maybe Ccleaner doesn't fix it I give up. It would have been easier to diagnose and fix if it would actually produce an error.

Alternatively you could get some obscure Linux benchmark live-CD to stress-test your hardware all in one to see if anything fails. I have no idea what it would be called but I'm pretty something like that exists. It sounds to me like your hardware is fine though.

 

[theSovietConnection]

Try a system restore to a date before this problem manifested. Sounds like it's a software problem more then anything, as if it were a PSU problem, I doubt it would go through the full restart process, it would likely flick off without warning.

 

[Zer_]

How do you know it works wonders? Have you got adequate testing equipment?

A 750w runs both my 5870s without issues. I am, of course running a Phenom II 965 with that.

Corsair is a top PSU brand, no doubt about.

I also happen to have a 750TX, and it's powering my i5 750 OCed (3.7ghz with turbo on), two 5850s OCed (from 700/1000 to 850/1200), a sound card, a GT 240 for PhysX, an SSD, two HDDs, and 8 fans. Pretty damn solid! I'd like to run some wattage checks and all that but don't have a multimeter at home (yet...).

I'd bet even a Corsair 550VX could power that system (the OPs) no problem.

Indeed. Honestly, skimping out on a PSU these days is a big no-no. In fact, you really can't afford to skimp out on much at all when it comes to computer hardware. You need a PSU that provides for a stable power output.

 

[BENZOOKA]

I'd rather not partition as I've had bad experiences with it before (namely, wiping out an entire drive instead of partitioning), but as a "last ditch", I'll just format and reinstall.

Without a doubt you should partition, at least make one for your OS and reinstall Windows. OS should definitely be on it's own partition. It also makes the future re-installations so much easier. Installing XP only takes two hours or so, drivers and most important software and games included. I just reinstalled XP on my sister's computer last night. After less than two hours I had installed all the drivers and a handful of programs.

It doesn't even hurt to get a fresh install of OS every once in awhile. I did it once every few months with XP, even more with 2000. It gets slow so quickly.

This shouldn't be a "last ditch". So far it seems as it is not about overheating/PSU issues/graphics card drivers/bad RAM. I assume you haven't done any overclocking? because that is a symptom from slightly unstable overclocking. Haven't turned even any automatic tweak switches on full/aggressive/turbo on BIOS lately? They shouldn't normally cause this kind of reactions, as opposed to manual overclocking, but it can happen. Other probable causes would be antivirus programs or firewalls clashing or breaking with their tangled webs in the registry, corrupted/broken registry and audio drivers gone crazy. But in these cases a BSoD or the game just freezing/crashing would be more expected.

I'd put my money on a fresh install of Windows solving your problem.

 

[Marowit]

When it was my MoBo it seemed like the restarts were almost random, and almost certainly when I booted up anything that took substantial power/memory. If I turned it on, and just let it sit there it'd stay on for a while before restarting.

When I booted it up and started watching stuff online, or gaming *boom* head shot and it'd reboot itself.

 

[Laughing Man]

40A alone for the video card? That's 480W - the card has two 6-pin connectors and a PCI-E 2.0 connector, meaning that it can draw a max of 225W.

Um no, the Amp rating given by card suppliers is a value including other stuff, so in general the 40A will include mobo, cpu, memory, one hard drive and one optical drive. Why you jumped to Wattage values at the end of the statement is anybodies guess as the most common issues are folk mistaking high wattage values on the PSU case as being a suitable PSU for driving a modern PC. Most issues come from having not a decent or solid enough Amperage level on the +12V rails since these values are very rarely mentioned or highlighted as much as the power ratings.

It doesn't even hurt to get a fresh install of OS every once in awhile. I did it once every few months with XP, even more with 2000. It gets slow so quickly.

This shouldn't be a "last ditch".

Worst advice in this thread so far. A reinstall of the OS should always be a last ditch attempt. Not withstanding the hassle of having to back everything up, then spending a few hours reinstalling everything, finding drivers for hardware, hoping that they all work as well without issues as your old set up did and then having to spend a day waiting for Windows to update your OS the worst factor is you have had a problem and instead of finding and solving it and learning something you learn nothing. What happens if the problem reoccurs 3 days after reinstall? You gonna reinstall the OS again?

Disable Windows Schedular and see if it helps. Sounds like a program has been given the right to shut down your PC once it has completed doing whatever it is that it does. Defrag tools, Windows update, virus scans they all can complete tasks in the background and then shut the coputer down when they finish. You'll need to look at what is running, what it does and weather or not it has been given the right to shut down Windows when it's finsihed doing what it does.