Consistent BSOD

I've been getting a consistent BSOD and can't seem to find the cause.

Here's the pattern:

1) Boot up after being shut down for a while (i.e., overnight).
2) Do whatever for some amount of time. Could be seconds or hours, browsing online, watching a movie, etc.).
3) Start up graphics-intensive game (fallout, elder scrolls, borderlands, etc.).
4) Within 1-5 minutes I get a crash. I don't actually get a blue screen, but the system freezes and I get a loud buzzing out of the speakers.
5) Reboot
6) Continue with no issues. I can go 24 hours running anything and have no problems at all
7) Shut down for a while
8) Back to step 1

I've tried:

Running the memory diagnostics tool, no problems found.
Going through every device in device manager, all drivers updated.
Going to Nvidia's website (my graphics card) and manually downloading drivers, no new drivers found,
Going to MSI's website (my motherboard), same thing.

So is it a hardware or software problem? It seems unlikely that it's a heat problem since I can get the crash right after booting up and then after restarting have no problems for hours. I have dump files but no idea how to read them.

A couple dumps are attached.