Monitor shuts off while gaming. HELP!

[sunnyd12]

Sup guys, my monitor will randomly shut off when I start playing a game like Call of Duty: MW2. It'll load levels and stuff like that, but once I actually start playing it shuts off and become completely unresponsive within a few minutes. It also did this a couple times while installing Win 7 or other large programs like Solidworks (CAD software). I have to restart my machine to get it working again.

I've tried replacing the RAM, running MemTest86, updating BIOS, and updating drivers. Starting to think it might be the PSU or maybe a bad GPU or mobo. Help please?

-Sunny

Gigabyte GA P55A UD3
Intel Core i5 750
Western Digital Caviar Black 750GB
Galaxy GeForce 9800 GT 512MB
G.Skill Ripjaws PC3 12800 4GB DDR3 RAM
Arctic Cooling Freezer 7 Pro
OCZ Fatal1ty 550W ATX12V ♠

 

[JackNaylorPE]

Download and run OCCT CPU, GPU and PSU tests. Check graphs for any temperature / voltage anomalies.

 

[sunnyd12]

Alright, just downloaded it. I'll report back in an hour or so with results..

 

[sunnyd12]

CPU tests ran with no errors. I'll run the other tests tomorrow morn and see how it goes

 

[sunnyd12]

GPU test failed twice. Well, it didn't really fail as much as my monitor shut off and the computer became unresponsive like it usually does. Temps didn't reach above 75 so I'm guessing it's just a bad graphics card. Hopefully replacing it will finally make my comp work!