i cant see anything in the game!

I have exactly the same problem. When I try to create the terrain or a game object like a cube or a sphere, I never see in the scene view what I have created. Of course the current object is always selected in the Hierarchy view and then pressed F over the scene view. But the only thing I see are the three axes and not the object along with. Please help. I tried uninstalling, redownloading and reinstalling unity but nothing is happening!