Blue Screen in Middle of Session

[Huntn]

I have a 2011 MBP (see sig), I've noticed twice in the last couple of days that in the middle of a session, the last time just browsing with Firefox, that I got a blue screen that did not go away. I admit I did not wait a long period of time before force restarting. On restart the problem goes away.

Any ideas on a likely culprit? I have looked around for "blue screen" links, but the ones I found had to do with a blue screen on start. This is not my case.
Thanks!

 

[Huntn]

Happened again tonight. Left the computer idle for an hour and came back to a blue screen. I could tell there were things going on in the background, just no video... Had to force a restart to regain video. I had a MBP once with a video problem and it showed in the profiler. Is a PCIe lane Width of x8 normal?
Thanks!

AMD Radeon HD 6750M:

Chipset Model: AMD Radeon HD 6750M
Type: GPU
Bus: PCIe
PCIe Lane Width: x8
VRAM (Total): 1024 MB
Vendor: ATI (0x1002)
Device ID: 0x6741
Revision ID: 0x0000
ROM Revision: 113-C0170L-573
gMux Version: 1.9.23
EFI Driver Version: 01.00.573

Intel HD Graphics 3000:

Chipset Model: Intel HD Graphics 3000
Type: GPU
Bus: Built-In
VRAM (Total): 384 MB
Vendor: Intel (0x8086)
Device ID: 0x0126
Revision ID: 0x0009
gMux Version: 1.9.23
Displays:
Color LCD:
Resolution: 1440 x 900
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Built-In: Yes

 

[Huntn]

I did update Firefox recently (14.0.1) and found this thread regarding Firefox updates and video. Hmmm.