As the rest of the system is unknown, it's possible that your PC doesn't fit what this TV needs in order to show such a thing.
For example on some sets if you set the input to Game or PC mode ALL video processing must be disabled since folk would scream LAG!!! as such transformations take time.
My bet is that it's not a feature for your PC sources.
Bob
Why cant i see 2d to 3d app on my lg smart tv

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic