[Zebodog]

I would probably try a basic install with no update and see if that works. If not install 1.67 and try again. If 1.67 doesn't work try 1.68. Try one at a time so as to eliminate as many variables as possible.

Did you try disabling sound and trying to run NWN? If it still crashes with sound disabled you can rule out your sound card.

At this point I'd probably also try reverting your drivers back to a 5.x version to see if it is in fact the newer drivers. ATI recognizes it as a known issue all the way back to 6.1. Directly from the Catalyst 6.1 release notes:

Neverwinter Nights: Playing the game under Windows XP on a system containing an ATI Radeon X800 series, may result in the game exiting to the Windows desktop and an error message being displayed. Further details can be found in topic number 737-21466