I dropped my iphone 4s and the screen went black? - 1

I can still hear sound but nothing else

It may or may not be busted. Take out the battery and put it back in. If that doesn't work, contact the manufacturer of the phone and see if there's a way to reset it. If there isn't, you might have to replace it or get it fixed.

If your contract is up, then I would just trade it in and get a new 4S free. You would actually get something back for the broken one too.