I dropped my laptop about 6 months ago and since then the cd drive has not read anything.?

You have a broken CD drive. The fact you you cannot see anything broken is meaningless. CDs are optical drives and work by focusing a movable Laser through a lens for reading and writing. It doesn't take much to cause the lens either not to move, crack, or have the Laser itself not work. My feeling is that the lens is stuck and will not move back and forth hence the black screen as it cannot read the beginning of a CD but is still reading something.