MSI 870A-G54 AM3 motherboard going bad?

I built my computer about a year ago and I haven't had any real issues with it until now.

I got Battlefield BC2 on Steam and Since I started playing it'll play fine for about an hour to two hours then all of a sudden my computer will completely lock up. I can't do Ctrl+Alt+Del and no matter what I press nothing on the screen changes. The sound basically cuts out when it happens. The only way to get it working again is to power cycle it. I haven't had it do this doing anything besides playing battlefield. I checked Event Viewer and the only thing it mentioned was the computer being shut down improperly.

I've run memtest86 and everything checked out. so I don't think it's the RAM. The Power Supply seems fine too.

Any help would be greatly appreciated.

What have you done to test the PSU?

How long did you run MT86+? and was it the most current version?

I've had a similar experience, and it turned out to be my GPU. Perhaps putting some extra stress on the GPU would cause the lock up to happen faster. Download FurMark. Note: FurMark runs in fullscreen mode and causes your GPU temps to elevate to higher than normal temperatures, so don't be alarmed if you see your GPU at 80°C+. If the system locks up you'll know because FurMark will stop calculating.

If FurMark crashes (which typically will happen w/in the first 30 minutes), you'll see dots all over the screen image. This happens because the data being sent out by your GPU is corrupted. The data gets corrupted because the GPU gets too hot.

i went ahead and ran Furmark. I have a 6850 though and if I remember correctly they have protection against it. The highest temperature I got to was 77C

I tried disabling the audio like it said in the post here EA Forums
and it still crashed like usual.

Anyone got any ideas?

Your 12 volt was showing close to 14 volts???? Is that not out of spec?