Nikon D5100 Troubles? - 1

I accidentally dropped my lens and for about a week whenever I tried to attach the lens, I would get a message on the camera that said "No lens attached". After messing around with the lens, I found the problem and I can now use the camera. The problem is it isn't adjusting to exposure or auto focusing anymore. I only dropped the lens not the whole camera. Any ideas for how to fix it? I let a friend mess with the camera some too and I don't know what settings they changed. Do I need to get a new lens or send it back to Nikon?

A dropped lens is a bad news. DSLR lenses have plenty of tiny components which are finely assembled. Dropping the lens may cause these mechanisms to break apart and stop working.

Try putting the DSLR on Full-Auto mode. This is the quickest way to check for auto focus/auto exposure functions of the lens.

My guess is that the lens needs servicing.