As best as I can remember, ever since I got my computer (built by someone else) over a year ago I've been having very unusual crashes and BSOD's. First I'll describe the crashes.
These crashes only occur as far as I can tell when running games, specifically 3D games, but the crahes are not game-specific. Furthermore, they only occur on some boot ups. What I mean is, if I boot up (or restart) the system, the crashes will either happen within the first 10 minutes of playing a 3D game, or they will not happen at all. Even if I play for 8+ hours. They won't happen say, 30 minutes in, ever.
The crashes vary somewhat, but they are all tied together and all seem linked to nv4_disp.dll driver. The most common crash is a blue screen. Example:
However, sometimes the crashes will simple close the program (game) and blame the game's .exe file. However viewing a minidump of this points to nv4_disp.dll again.
Again, these crashes only occur while 3D gaming, and only on SOME boot ups. If I sit down and reboot my system 20 times, each time attempting to play a game, probably 5-10 of those bootups will result in the BSOD crash.
Now on to trouble shooting. First my system:
Intel Core2 Quad 2.4 Ghz
4 GB's RAM (3.25 recognized by windows)
Win XP Pro all updates.
Nvidia 9800GTX+ 512 graphics
Intel D975XBX2 motherboard
soundblaster live card
Getting desperate, I have now tried a complete format (after updating my bios to latest), reinstalled XP pro, installed chipset drivers and LAN drivers, updated XP Pro, installed latest Nvidia drivers (257.something), installed Steam (game service), and installed Dirt 2 (a racing game). Exactly in that order, nothing else. Crashes still occur. Next I swapped in another video card (nvidia 7900 GS 256 MB). Crashes still occur, same as always. Went back to original video card, ran windows extended memory tests. Memory is fine. Checked harddisks for errors, no errors. Ran futuremark 3D and furmark (video card benchmarks and stress tests), no problems.
So I'm completely stumped. I can't even imagine what might *hypothetically* be the problem at this point. What could cause these crashes on some boot ups, but not on others?
Any help or suggestions or ideas would be greatly appreciated.