Is my Power Supply or Graphics Card Dying?

When I run Diablo 3 my computer restarts without warning at the login screen. The things I've tried so far are changing the video card slot, and changing the cable going into the video card. At first I though it was my processor over heating but when I ran prime95 everything checked out, so then I got a GPU stress test and after about 30 seconds my computer shut down without warning. The program I used was FurMark.

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz, Intel64 Family 6 Model 42 Stepping 7
Processor Count: 4
RAM: 8153 Mb - Crucial Ballistix Sport 8GB 2X4GB PC3-12800 DDR3-1600 1.5V CL9 Dual Channel Memory Kit
Graphics Card: AMD Radeon HD 6800 Series, 1024 Mb - 6850
Hard Drives: C: Total - 152624 MB, Free - 96348 MB; D: Total - 99 MB, Free - 70 MB; E: Total - 953766 MB, Free - 769338 MB;
Motherboard: Gigabyte Technology Co., Ltd., Z77X-UD3H
Power Supply: Sparkle Action 700W Model #: SPI700GLN
Antivirus: Microsoft Security Essentials, Updated and Enabled

The motherboard and ram is brand new and this is a fresh install of Windows 7. The graphics card is going to be about 1 year old in June, but the PSU is the only piece of original hardware on my computer which is about 5 years old and not really that great of a brand so I'm thinking that it's about time to replace it.

Should I go out and spend the money for a new PSU, or is this actually a graphics card problem?

 

The power supply is within limits, but if I started with a new Mobo, I would start with a new PS....A five-year old power supply is reaching the beginning of the end of it's natural life..

 

I agree with ekim68, a power supply that old is probably just waiting to fail at a very inoportune time, if it isn't the problem now, it may well be soon. With the new motherboard I would replace the power supply with a quality manufacturer unit, such as an OCZ, Corsair, PC Power and Cooling, Seasonic.

 

Thanks a bunch for the confirmation guys really appreciate it. Hopefully the new one comes in quick!

ps. I'm blaming you guys for all my problems if they still occur.

 

Well I've had this same problem. I'm running the same graphics card and a new power supply only a couple months old. I've found this problem happens only on high end games such as Star Wars the old republic and Diablo 3. I thought I had found a way to bi-pass the problem when I hooked up two monitors it stopped it from happening for a few weeks. But today it started up again. I believe it has something to do with the graphics card. I can't seem to find a fix for it so any help is much appreciated.