Let's get one thing out of the way first:
Turn off Draft 3D so that we can see how the composition looks in the Composition panel with this off.
It looks like you have draft 3d turned on in your comp which turns off the effect of lights (and shadows and motion blur). When you render, however, you're seeing it with the all of those features on. So either work on the light so that it does what you want it to do or turn it off.
What the others said - you have draft 3D enabled (which ignores 3D lights) and for final rendering at fuill quality your light setup is not right so the objects and effects are unshaded "black holes".