Sorry, I meant back of the screen. Inbetween the keyboard and screen there is a ribbon that connects the screen to the phone(keyboard). It may have come out with the impact, which means that the screen, mic, and touchscreen would not work but the phone powers on regardless. It's worth checking if you want to repair it yourself. You can see the ribbon here.

http://www.youtube.com/watch?v=aVEHm325-z8

Somebody had this problem in the past:
http://talk.maemo.org/showthread.php?t=45296