Yikes!!! I haven't heard of that video card before...I must say that the problem may be unfixable. However, the 'good' news is that if you made it past Otoh Gunga, you won't have any further situations like it.
There is something you can try if you want to play through Otoh Gunga - you can use the cheat code that brings the camera in lower. Hit the Backspace key, then type in "naughty naughty", and press Enter. The camera will move in close behind your character, allowing you to see forward. This might help you to see, but it will make some of the jumping puzzles quite difficult
Also, one side effect of the cheat is that sometimes during in-game cutscenes the camera gets REALLY unhappy.
I'm sorry to hear that the Additive Blending didn't work...I'm actually surprised to hear that.