Ipods dropped it and it cracked at the top too.

SO i have an Ipod 4th gen and it was working fine. But i dropped it and it cracked at the top too. It was bad.. :P Over time the glass on top started to fall off so i tapped it and it was fine for a long time. some times i have to press on parts of it to make it run faster. but tonight when i touched it., it made my entire screen go white. I tried the whole off buttion and home button and the up volume with the two buttons, itunes wouldn't let me do anything because it has a password and i can't get to it :( and i don't know how to fix it? Help me please