There's a stereoscopic 3D example on the NVIDIA developer website. Try running that and see what happens. http://developer.download.nvidia.com/SDK/9.5/Samples/samples.html#StereoAPI
I don't know if stereoscopic 3D still has to be enabled by driver specific flags (I once accidentally enabled stereo 3D for OpenGL games by mistake back in 2004-05). This is a subject I know little about but wish to implement using vendor independent methods using the right vertex and fragment program algorithms.
Also, I found this article (not sure if it helps or not): https://developer.nvidia.com/sites/default/files/akamai/gamedev/files/sdk/11/3DV%20-%20BestPracticesGuide.pdf