Why doesn't the iPod turn on after a screen replacement?

Hello. I am having trouble getting the Ipod to turn on or even display a screen after replacing the Lcd/Digitizer since i cracked my old one. I have over checked the cables for the screen and the digitizer so, I know it's not that. I have also tried the technique about touching the battery terminal and the ground but that didn't work either. I am not sure what is going on? I unplugged the old screen when the Ipod was turned on. I am not sure if that has anything to do with. If i could only tell if the battery is even charging or any sound that the Ipod is turning on then I could tell that it's just a bad screen but I don't know how to tell that either since it wont turn on? Any help is appreciated. Thanks