BleepingComputer.com: Random Vista Crashes - atimkdag.sys Message

I am posting this in the Vista setion because I have not been able to isolate any hardware component that is likely to be the cause of the issue, and am looking for some advice on how I can proceed to correct this problem.

The issue I am having is that my computer display will go blank for several seconds and display the message "Video driver atimkdag.sys has crashed and recovered", or it will go blank and come back several times before going to a blue screen of death. I have searched for information about this error message, but although I have seen many posts from people who have the issue, I have not seen any fixes. The problem seems to occur regardless of what programs are running. The problem does seem to occur mostly when I have two monitors connected. That is the only commonality that I have found so far.

My system configuration:
Enermax Galaxy DXX EGX850EWL 850W power supply
Intel Pentium D 945 3.2 Ghz Dual Core Processor
Intel 945 PSN Motherboard
2x 1Gb 5200 RAM (paired)
2x 512Mb 5200 RAM (paired)
ATI Radeon HD 3870x2 PCIe Dual Core Video Card (previously had ATI Radeon HD 2900 XT PCIe)
SoundBlaster X-Fi Extreme Gamer Sound Card (previously had SoundBlaster 24-bit)
GE Internal Dual Layer DVD R/W Drive
3x Hard Drives
Windows Vista Ultimate Edition x64 SP 1

Steps taken to resolve issue so far:
Reinstall Windows Vista numerous times.
Replaced video card with different model.
Replaced sound card with different model.
Replaced RAM.
Updated motherboard BIOS.

Are there any other steps that I could take to narrow down the cause of the problem and resolve it?

Some reading here:
http://forums.amd.com/game/messageview.cfm...threadid=104677

Thanks! That is by far the most comprehensive article I have seen about this issue. Unfortunately, so far it has not led to a successful fix.