Freezing screen with distorted verticle lines

Hello everyone. I've mostly lurked around and found a lot of good advice for some of the issues I've had in the past, but can't seem to find an answer for this one.

The problem that I am having is that when playing WoW, my screen will randomly freeze and I see distorted verticle lines of the frozen screen. Its like looking at a screen shot, but its broken up vertically. At this point, I have no control over my mouse, alt/tabbing to other windows, or any functionality really. Other programs are still running in the background because I can still hear music playing or people on ventrilo. I haven't been able to replicate the problem at will, but it has happened on 3 separate occasions now within the past week.

I first thought it was my video card over heating. I'm currently running a BFG GTX 260 Maxcore. GPU-Z logs showed highest recorded temp during intensive graphic scenes (aoe on whelps at the beginning of onyxia p2/initial aoe trash pulls in icc) reached 84C. I decided to manually set the fan to a constant 60% and it now only reaches 74-76C. Unfortunately that did not fix the problem as the screen ended up freezing on me the following day.

I'm not sure if this is a power/voltage issue as I am not sure how to check on that. I have an older model Antec 650 Truepower PSU that is roughly 2 years old. I'll list the rest of my components below. Oh, also using the 196 release of nvidia drivers if that helps at all.

Antec Nine Hundred Two Black Steel ATX Mid Tower Computer Case
AMD Athlon II X4 630 Propus
GIGABYTE GA-MA770T-UD3P
BFG GTX 260 Maxcore OC 216
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600
Seagate Barracuda 7200.12 ST3500418AS
Antec True Power Trio TP3-650