Screen Keeps Locking Up in Various Ways, Please Help!!!

[jxu101]

I recently built a new computer with:
Antec 900 case
2x2GB G-Skill RAM
Intel Core2 Quad 2.66 (Q9400)
Gigabyte GA-EP45-UD3P Motherboard Rev. 1.6
EVGA Nvidia GeForce 9800 GTX+
Corsair 650W Power Supply
running Windows 7 64-bit.

Now on to the problem: At seemingly random intervals (sometimes every 30 minutes, sometimes every 2 hours or so), my screen/computer just fails, and I have to reboot. The screen either:

-Freezes with my windows/desktop still there, can't move my mouse or type, and there is a buzzing noise coming from my speakers.
-Goes black, and there is a buzzing noise
-Displays this, no buzzing:

-Displays something like this, no buzzing:

I've yet to overclock, run any games, or anything like that: I'm just listening to music, chatting, and browsing the web. My core temps are all under 45C and my GPU is under 40C. Also, when the screen locks up, I lose connection to my iTunes stream to my laptop and can't connect via TeamViewer, so this may be more than a graphics problem....
My BIOS is version FB for the Gigabyte mobo, but the latest version FD doesn't really address anything i would think is associated with my problem, so I've yet to update that. (Description of the BIOS versions from Gigabyte) http://www.gigabyte.com.tw/Support/Motherboard/BIOS_Model.aspx?ProductID=3137


Does anybody know what might be the cause of the problem and any possible solutions to try?

 

[foothead]

have you tried running the computer with a different graphics card/onboard graphics?

It seems like your gpu is bad.

 

[jxu101]

haven't been able to yet. EVGA recommended I try using my video card in another working computer, but my friend who has pretty much the same setup as me is out of town, so I'm waiting on that. Some others have suggested that the video card may not be the (only) problem, so I wanted to get more opinions by way of forums... but I guess the GPU may really be the culprit, if you guys think so

 

[foothead]

just yank it out and plug the monitor into onboard graphics. It'll just take a few minutes and give a more clear answer.

 

[jxu101]

my motherboard doesn't have onboard graphics. i'm going to be swapping the geforce with a friends (same model) to see if that's really the problem. if he starts having problems and i don't i'll be able to tell it's the video card

 

[jxu101]

So I haven't been able to trade video cards yet, but it turns out many people have issues with the GSkill F2-8500CL5D-4GBPK RAM and the Gigabyte mobo. So I moved applied the voltage and clock settings as listed in a sticky on the gskill forums, and I'm still getting the same issues pretty much. I was able to run Memtest86+, and it turned up 0 errors over 5 passes. Does that mean that the RAM and Gigabyte mobo are working together in harmony fine with my current settings, or does that just mean there's no issue with the RAM itself (strictly hardware), and that an incompatibility could still be the culprit?

update: traded video cards with my friend, and my system failed after 3 hours, and his system has yet to (and I don't expect it to) fail with my card. looks like I'll be doing some RMAing with newegg. Opinions on the matter? RMA both the mobo and RAM? just the mobo? just the RAM? RMA for a refund and buy a different brand of RAM/mobo?