Weird random crash

Question

When i am playing games, sometimes i get a random crash. The crash is like the game freezes, the sound starts repeating really fast, almost like a buzz. The only thing to do is hit the reset button. Once i hit reset, the post code indicates a video error, (ami bios, 1 long 2 short). But if i power off, then power on the post screen comes up and says "The previous performance of overclocking is failed" (even though i was not overclocking!!!) I then hit space bar to go into bios, save bios and exit, and everthing is fine.
This is generally during games, it started with far cry 2, i thought it may have been an issue with the game, but then it showed up in crysis warhead, the witcher, and most recently arkham asylum among others. In arkham it seems to happen at the end of the combo when it goes into slow motion knocking down the last bad guy. But other than that i havn't found any patterns.
it would also happen whenever i tried to update the same game with the ingame windows live update.
this seems to have appeared after i changed processors, but ... read on
I am fairly confident it is not overheating, all system temps remain stable and system is well cooled.
I have stress tessed the cpu with 4 windows of cpu burn in, for around a day long, with no issues, also stress tested with prime 95 for a long (approx 20 hours ) period with no issues and good heat dissipation, so it makes me wonder if it is the cpu?
I have stress tested the video card with ati tool, video card stress test, furmark ozone3d, and 3dmark 06 with no issues. furmark raised the temp way higher than any game has and nothing wrong.
I updated motherboard bios thinking maybe it was an issue that had to be straightened out with the chipset, but no difference. (before i update i had ami v1.8, and instead of 1 long 2 short, it was 8 short beeps, but both are video card related)
all drivers are up to date..
tested memory for 20 + hours with memtest 86+ and windows memory diagnostic, both reported no errors.
    * Motherboard brand & model- MSI k9a2 neo-r
    * CPU model (and is it overclocked?)- amd x4 940 be (at stock)
    * Video card(s) evga 8800 gt, 512mb
    * RAM modules brand & model patriot ddr2 800, 2x 2048
    * Power supply brand & model silverstone st50ef plus 500 watt
 sound blaster audigy 2 zs....
I am going to swap the 5000 back in, and see if it still occurs, since it showed up when i change to the 940, but just wondering if anyone had any input or seen anything similar before.  But the bios beeps referring to video problems also make me wonder, maybe the board itself can't handle the cpu. 
Thanks

Answer 1

Ok, so I think i have made some progress, it doesnt seem to be the cpu.. but it is the video card.  I did a few more stress tests and noticed that the card (using furmark) was reaching 100+ degrees C.( while cpu stayed in mid 30's)  Around 105, boom, computer crash.  I didn't think I was reaching this high of temps in games though, so I need to find a way to monitor the gpu temp in games. It is kind of weird that this started with the new cpu though.... but i put in a new cpu fan as well, I added a xigmatech hdt -s1283, so maybe it changed airflow or something?  I need to explore this a little further tomorrow.  Will also apply some mx -1 paste and reseat the gpu heatsink.  and improve case airflow if possible. 
This is kind of puzzling still, because from alt-tabbing in and out of games, or looking at evga precision after a session, the highest gpu temps are typicall less than 80 under load in games.