3d conversion

I have a question, so say if i got an nvidia gpu, glasses and have the required monitor, does that mean i can watch 3d movies? What about converting 2d into 3d? Or do i need some special software along with all this. i cant seem to tell, to me it seems like you only need a nvidia gpu card, monitor and you can pretty much watch anything.
And converting from 2d to 3d probably doesnt give much 3d effect im guessing?
Thanks