I have a DVD/Cd drive, well its a DVD/Cd burner (BenQ)...

Recently it has been unable to read DVDs, it can however read and burn CDs.
Why can't it read and burn DVDs?

When I insert a DVD nothing happens, when I check the Drive - I go to my computer and click on Drive E it shows nothing. When I attempt to burn files off my computer onto DVD it says please insert DVD, when there is already one in there.

I am in desperate need to fix this problem. Can any one please help me?

Thank you so very much.