Windows 7 Frequent Hard Hangs?

i've been having major issues with my pc that i built roughly 3 months ago. I've been trying to figure this out for about a week now but i'm really at wits end here.

The Build:
Phenom x5 955
Radeon 6870
ECS A885GM-A2 Mobo
Ballistix 8 gig ram

The Problem:When i boot into windows 7 it works for about 5-10 minutes just fine before it hard hangs. This problem started roughly 3 weeks ago, but the lockouts were so infrequent i figured it was just random glitches. Now, this lockout occurs every time i try to start my computer in anything but safe mode. I've never seen a BSOD before, the computer just locks up and becomes unresponsive to all inputs. If a video or some sound was playing at the time of crash the speakers also play a "brrrrr" noise. It even occurs if i boot the computer and just let it sit there without running any programs whatsoever. Since building the computer i have not added any major new hardware or done any drastic changes other than download or install fairly banal programs.

What I've done:
Updated graphics card driver
Checked Bios Version-up to date
sfc /scannow returned no problems
Error log shows nothing but "kernel 41 power critical error"
Taken apart computer to look for any hardware damage

From my research this "kernel 41 power critical error" is a fairly widespread problem but no one seems to have one set solution for it. I really am out of ideas and frustrated beyond belief.