BSOD, CPU Hot Tester errors

[AnimalHungry]

[MODS: Not sure where to post this so feel free to move it. Thanks!]

I'm running Windows 7 on a Gigabyte 990FXA-UD3 mobo with an AMD FX-8350 CPU, 16GB of GSkill Ripjaw RAM and a Radeon HD 7970 video card (see CPU-Z summary here for more system specs: http://valid.canardpc.com/e929ul). My RAM voltage is set to 1.5v and the timings to 10-11-9-30 2T per the GSkill recommended settings and that's been running fine for about a year.

I've recently been getting a BSOD: a page_fault_in_nonpaged_area error. So I started to troubleshoot it by first testing my RAM stick by stick in Memtest and it froze the program with an Unexpected Interrupt - Halting error (see screencap below). I Googled that and it pointed towards a CPU or mobo error, so I then run a test in Windows using Hot CPU Tester and it fails at 90% on the first Complex Matrix test. At first it just failed, wrote a dump file, and then moved to the next CPU and failed on each one and only BSODd on the final CPU, but now it fails on the first CPU and goes to a new memory_management BSOD (see below). Here are links to the minidump files Hot CPU Tester created - I have no idea how to read them but hope they might be useful:

http://www.filedropper.com/hctfeb23-093822
http://www.filedropper.com/hctfeb23-093833
http://www.filedropper.com/hctfeb23-093912
http://www.filedropper.com/hctfeb23-094422
http://www.filedropper.com/hctfeb23-094512

I Googled that and some thought it might be a hot CPU/heatsink incorrectly seated, so I removevd the heatsink, cleaned it up, replaced its fan with a new one and reapplied thermal compound and reseated it. My CPU temps dropped a bit (now idles at 10C) but I still get the BSODs while running Hot CPU Tested and the interrupt error in Memtest.

Any ideas what this might be or what I could try next? Any ideas greatly appreciated!

Cheers
Simon

EDIT: my linked images aren't appearing, so here are the links:

BSOD #1: http://www.filedropper.com/img5494
Memtest error: http://www.filedropper.com/img5496
BSOD #2: http://www.filedropper.com/img5501

 

[AnimalHungry]

So I just flashed the mobo BIOS and managed to run Hot CPU Tester for 20 mins with no errors - previously it would throw an error almost immediately then BSOD within 10 mins. I'm now running Memtest which, so far, looks good.

If the mobo BIOS upgrade has fixed the issue then I really have no idea what the underlying issue was since I haven't installed any new hardware/software in a while. But whatever, no use looking a gift horse in the mouth. I'll post back in a few days to confirm my PC's stable in case anyone else has this issue.

Cheers
Simon