Since this seems to come up a fair amount, I decided to make a sticky. This thread contains a lot of solutions on how to deal with newer NVIDIA cards and Infinity Engines games. Also, feel free to contribute to this particular thread. Hopefully it will be of some help.
Thanks for the link, I remember trying to run PS:T on my machine (with an 8800) and it wasn't even playable. Glad to see that it should work now!
I just dug up another thread that deals with the issue... since I decided to give IWD2 another chance and was experiencing the blocky, and forever advancing fog-of-war problem myself. I ended up disabling hardware acceleration: Start > Control Panel > Display > Settings > Advanced > Troubleshoot Worked like a charm!
Wait...my game freezes/crashes at the same point in IWD2, and I cannot progress any further because of it. <*Possible Spoiler*>It's the point in time where you must talk to Oswald to begin Chapter 2, after you return from the Goblin Fortress where you save the two scouts from Targos.<*Possible Spoiler*> Could that be a problem with the game itself, or a problem with my computer/graphics card? I have tried looking it up, but I have not read about anyone experiencing a similar problem. I posted a thread about my question (which you can view here), along with other problems I have experienced. I have never had such problems with BG1 or 2, and my Dad never told me about any problems that he had with the games, but its been a long time since he's played them. I hope I can get some help so that I can finish the game!