BSOD 124 and C9, among others

[perforations]

I've had a couple BSODs over the past couple months, but very recently they have been popping up more often.

I recently installed Skyrim and since then have been getting BSOD with error code 0x00000124 frequently, usually when doing something 3D. One time pixels the color of my desktop background started flickering around the screen, and once while playing Skyrim rainbow colored pixels were all over the screen, then proceeded to BSOD. I would cast blame on the 2 (or 3?) year old GTX 260 but I also received a BSOD code 0x000000C9 (truecrypt.sys) when trying to start up TrueCrypt.

Upon replacing the video card with a low-end one, the same black screen happened, my BIOS complained and proceeded to BSOD when starting Windows (0x00000124 again) but hasn't done so, so far, even under the stress of 3D games. Running TrueCrypt seems to work too.

In addition, sometimes my computer seems to boot but nothing is displayed at all to the monitor, only a black screen, and the monitor seems to be asleep.

My System:
Windows 7 SP1 (32bit)
AMD Athlon 64 X2 5600+
Gigabyte GA-M57SLI-S4 Motherboard
4GB Corsair RAM
Nvidia GTX 260 Core 216
Antec EarthWatts 650W

Things I have tried that have not changed anything:
Increasing CPU and Vcore voltage a bit.
Installing new sound drivers.
Installing new nVidia drivers.
Specifically stress testing the CPU/Memory/Video Card (strangely no BSODs here).
Distributed.net CUDA client didn't seem to cause any problems.
A couple passes of Window's MEMTEST.
Swapping out the 4GB of RAM for older 1GB sticks (2GB total).
A virus scan using MSE.
CHKDSK before boot.

Is there anything else I could try to be sure it is my video card bugging out and not my motherboard or CPU (or even power supply)?

 

[xunicronx]

Do you know if you have TrueCrypt version 7.1a? Maybe the vRAM on the GTX260 is going bad? I think you "may" have to clear the CMOS because of the memory change (maybe). Who is the manufacturer of the graphics card, please.

 

[perforations]

I believe TrueCrypt is 6.2, according to the .exe properties. EVGA for the GTX 260, sorry.

Is there any way I can test the VRAM?

Also I just booted back up with the GTX 260 and it took 4-5 tries to actually get Windows going fine. A few black screens and then a couple BSODs.

edit: I just tested it with memtestCL and memtestG80, neither of which caused any BSODs or reported errors. Also ran around in Minecraft for a bit. I tried running TrueCrypt again as well and it opened fine. The only difference right now is that I still have the 2 GB of memory seated instead of the 4. I'll try and run more extensive tests on each later/tomorrow and then update.

 

[perforations]

Today it took 4-5 black screens before POSTing, and a few BSODs while loading Windows. I swapped the 2GB of RAM to the other two DIMM slots and it took 1 black screen before booting Windows, and here I am now. No big problems so far except the stupid 296.10 drivers failing... I'm leaning heavily towards the motherboard right now.

edit: It stopped booting, video card fan seems to start but stop after one second. I can only presume that the video card had indeed died. I ended up getting a new machine but kept the PSU, so that wasn't it.

 

[perforations]

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