The computer in question is an Asus M3A 79-T Deluxe, AMD 940, 4G Corsair Ram,  Evga 4870 (2)

The problem srarted when I turned my computer on and it refused to boot. Would get to the final stages of booting and would get a Video Not Detected error.

After playing with it a bit I used Drive Cleaner and removed the Video Drivers and the system booted fine.

I downloaded the CAT 9.5 drivers and installed.

When I rebooted I got the same error and the system refused to boot.

I went as far back as CAT 8.1 and worked my way forward back to CAT 9.5 and continually had the same problem.

By this time I had stripped the computer down to the bare minimums trying to eliminate any other hardware problems.

I loaded my HDD caddys with 3 new HDDs, loaded Windows 7, Vista64 and XP32 each on its own HDD.

Each OS did the same thing and refused to boot with any form of CAT driver loaded.

By this time I was only loading the drivers and not Cat Control.

I finally pulled my GTX295 out of the other computer installed it and the drivers and the computer booted fine.

I loaded the 4870s into the computer I pulled the 295 from, installed CAT 9.5 and booted the system with no problem

The computer that originally held the 4870s worked great for months and just decided not to boot with the ATI drivers.

Any suggestions would be greatly appreciated.