Anti Aliasing with 250 gts in 1946

[IceFire]

Could be some deeper issue. Sounds like a pain but remove TrackIR, Freetrack, whatever else you feel might interfere with the game.

Uninstall all of the nVidia drivers and then run some sort of driver sweeper... I used to use this one: http://www.guru3d.com/category/driversweeper/

Once you're free of all of this stuff get the latest nVidia drivers from their website and install those. See what happens. If you still aren't getting AA in OpenGL applications I'm not sure... but that speaks to some sort of deeper OS issue. It's very likely not a hardware problem...