BSOD unless GPU is underclocked

Hey, so I've been suffering from BSOD's whenever my GPU is under load for about the past year. (Not CPU, I can still do/play things that don't rely on the GPU fine, like Kerbal Space Program for example) However, since I've been away from my machine for college, my any improvement's been pretty slow.

Some things, like furmark, or skyrim crash my computer almost instantly, while it can last longer on older/less stressful things (Metro 2033, Civ V on direct X 9). Recently I've found that underclocking my GPU helps to alleviate some of the problem, but that's not really a fix, and the issues still persist in the most intense programs (furmark for example).

The SF diagnostic file is attached

My system specs are (sorry if it already says, I filled them out during registration, but I've just only joined here.):
CPU: AMD Athlon II X4 620
GPU: NVIDIA GeForce GTS 250
MoBo: ASUS M4A79XTD EVO

While my computer is starting to show its age, I'd really like to have it up and running again. Thanks for the help!

Edit: forgot to add this, but it often also makes a high pitched noise when it's about to crash. It's a pretty distinctive sound.

What power supply do you use?
When you put a load on a video card you are also putting a load on the power supply.

A sever year old unknown power supply is pushing your luck.

I will not go off site to view logs.