Slide to unlock not working

I recently replaced the screen on my iphone 4s and the slide to unlock wouldnt work and I ordered another screen still the same problem with the unlock and keyboard. The phone was ran over by a forklift but only busted the screen and back glass. I can push both buttons and it will take a picture but I cant get off the unlock screen. Please Help!!!

I found the small rubber piece your talking about but not sure where it goes? Maybe under the screen somewhere?