Strange Video Problem.... Help?

[Burritoclock]

Bare with me here, this is a strange problem...

Got my new build put together, first build in 6 years, ran like a dream, OC the 920 to 3.5 stable, temps hold steady at 70c and thats with the exhaust fan on backwards... which is awful (all fans blowing in! will flip it today). I'll but my specs below. (No one I know cares about computers at all, sorry for the boring intro)

Anyway, as I said, ran like a dream, I even OC'd the video card (A simple cheap Radeon 9730) and everything ran great. Then one night the monitor begins to blink. At first I though it might be the monitor, but I reset and went into safe mode and the blinking stopped. So I rebooted and everything was fine, but I put the video card back to stock speeds just to be safe. Everything ran fine for a day or so, so I upped the Video card again, thinking that I would just up it a bit to test it. I ran gpu-z and atitool, the temperature was around 51c and the artifact test ran for about 45min with no problems. I figure it's ok, and go about using it. That night the monitor starts back up, so I do the whole routine again and it is now running without issue.

Now I have learned my lesson and will not be messing with the vid card my questions are:

1: Do you think my card is faulty and is a time bomb?
2: Could it be the power supply?
3: Could it be the monitor even with all of the above?
4: Would a driver issue cause any of this?

I am kinda stumped, from researching the interweb tubes I have found all of the above to be possible...

Thanks for any help, I have been lurking around here since I decided to build again and love this place, finally signed up.

Specs: (because of potential power issue I listed everything, like the stupid card reader)

GIGABYTE GA-EX58-UD3R X58 ATX Intel Motherboard
Intel Core i7 920
G.SKILL 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333
SAPPHIRE 100265L Radeon HD 4830 512MB (9.1 driver)
Western Digital Caviar Black 7200 RPM
CORSAIR CMPSU-750TX 750W ATX12V
ZALMAN CNPS9700 CPU Cooler
DVD Burner
3.5 52-in-1 USB 2.0 Card Reader
Small little external USB hardrive on usb power
Vista 64


Is this the wrong section for this question?

 

[theAnimal]

1. Faulty, possibly. Time bomb, no. Try another card if possible.
2. Probably not, way more power than you need.
3. Possibly, try another if possible.
4. Possibly, try older version.

Have you stress tested your CPU overclock for a considerable length of time (8+ hours)?