So my suspicions were correct.
Like most other forums, most people here seem to refuse that Nvidia drivers cause issues.
Behind all the "ATI DRIVERS SUCK" threads are people whom are in denial about Nvidia's equally dodgy drivers.
I don't think anyone, including the OP, have proven the specific cause of the problem. He's on a pretty old model of card, and it might be he just hasn't tried the best driver version for it yet, or has BIOS corruption, or even a problem with his Pci-Ex bus or slot the GPU is in.
Finding which driver to use for older GPUs (with literally no help from Nvidia because they have no such database) is about the only real caveat of using their product, but it's not hard to find the best driver via Googling since SO many people use their product and have already done such trial and error testing.
Both ATI and Nvidia have driver issues at times, but after owning both for several years each, I have found Nvidia to be far more consistent at their new driver versions working right, they're quicker at fixing problems when they don't, their SLI consistently works better than Xfire, their installer is FAR better and does clean installs, their software in general is more stable, quicker to load, and less bloated, and they also have better long term driver support on older GPUs. With my X1950Pro it was relegated to Legacy support only, about a year before I stopped using it.
What really woke me up though was a call I made to ATI HQ in Can back when ALL MoH titles suddenly stopped working when Cat 5.7 was released. It had already been an ongoing issue for weeks, and there was an effective workaround a Rage3D forum member mentioned that people had to use to get by.
When I mentioned it to the ATI tech, he was not only oblivious to the problem, despite it being a pretty big game at the time, he was very snobbishly implying those complaining probably just didn't know how to install the game or the drivers properly, even though I had just told him I used the workaround mentioned on the forum with success.
The ATI driver just wasn't able to open the OpenGL API properly, so you had to extract the OpenGL driver in the game files, and place it in the game directory. On the rare occasion this happens with Nvidia in that game, it means you don't have the latest driver, Google for it. The ATI driver couldn't even do it with the latest version, and the "tech" was not only clueless when I explained that to him, he was persistently arrogant.
A few months later, a few MONTHS mind you, I saw in the ATI driver release notes for their next driver that they had finally recognized a problem with all MoH titles, and were working on a solution. Oh yeah, real good "support" ATI. When random forum searches produce better support than the GPU designers themselves, you know it's pitiful service, esp if you have to put up with attitudes along the way. Sticking with Nvidia, and no regrets.
When I was on my ATI cards I always looked for Omega drivers. They're basically streamlined ATI drivers with bug fixes. Angel "Omegaman" Trinidad was right when he constantly related to how bad ATI's installer is, and what a PITA it was to dig into their drivers each release and find out how many problems they had with them.
There was a short period that he was making Nvidia driver tweaks too, but that was mostly right after they started using SLI, and those problems are pretty much in the past. ATI had big problems right after implementing Xfire too, in fact they still have issues with Xfire.