If you are having problems with NWN crashing or your computer overheating, make sure you have vsync (found under Video Options -> Advanced Video Options) turned ON.
Without vsync, your computer will believe it has permission to run the game at an entirely ridiculous framerate like 150 or so, when 60 is usually ideal. This can literally melt your video card!!
If you aren't sure what your FPS is, I recommend Fraps! It'll put your framerate in yellow numbers at the corner of the screen so you always know!
While this won't fix every possible issue ever, in my experience so far, this has been the cause of most problems with the game.
