I played Civ IV for years without any difficulties on Win XP SP2, but recently upgraded to Vista (yeah, I know, I was asking for it). Now I get random black polygons all over the terrain and even the globe on the menu splash screen! Here's what I'm seeing:

http://i531.photobucket.com/albums/dd351/brightsun66/civ4.jpg

I've looked at all the threads for DX9 vs. DX10 and even went so far as to download and install the DX9 SDK as an attempted fix. I discovered I was using the default Vista driver for my graphics card (nvidia GeForce 6600 GT), but taking the very latest Vista drivers hasn't solved the problem, either. Any thoughts?