I've been having same problem as you last couple of months. My combo is the same, i7 930 windows 7 pro 64b, hd5770, ga-ex58-ud5.
I get bsod 124 only with Battlefield Vietnam and Webroot Antivirus. Apart from these two programmes, everything else runs fine.
When I boot up in windows xp mode (dual boot, not in win 7), I can run these two normally. But I dont want to boot up in xp, I want to run it in 7.
Like you, ive run memtest and have taken parts back to dealer to get tested and everything works and runs as it should. Its REALLY FRUSTRATING!
There's a compability issue here somewhere (code or hardware) and I wish someone would fix it.
Everything i have is updated, drivers, windows.