It sounds like you have the laptop screen, AND the HDTV screen going at the same time?
Seeing the desktop only is typical of what you see on the second (extended) screen. You can usually drag programs between screens so not quite sure what your problem is.
You can try rebooting the laptop, or experiment with dragging programs... other fixes include:
a) disable laptop screen (so only HDTV output is working so you'd see that just like laptop), or
b) setup CLONE mode so same content on both screens (may need to mess with scaling to setup properly)
*On the laptops I've used there's a quick way to toggle between screen modes... find the FUNCTION toggle key then press the F-Key with the screen image which may look like a square with a vertical line on each side. Mine toggles between laptop only, HDTV only, cloned mode... something like that.
Alternatively go into the VIDEO CONTROL PANEL (for Intel, AMD or NVidia as applicable) and manually setup things.