Not that this is any help, but I use TheaterTek DVD software and have no issues. My 6600GT nvidia based card worked great right out of the box. However, recently I tried upgrading the drivers to the latest nforce version online. Sorry, I don't remember the version off hand, just came back from the bars with some buddy's from work.
Anyway, with the latest nforce drivers I had problems vertically stretching 2.35 movies, which is the prerequisite of my anamorphic lens to get rid of black bars.
I had to roll-back my drivers to their default, and I am fine now.
