Iphone 5 wont turn on after replacing LCD

Hello everyone,

I just recently replaced my ATT iphone 5 LCD screen, because of the crack on the screen. After replacing it, it turn on and off very good. However, i noticed that there was a slight gap on at the top of LCD screen and phone, so i went to try and pop it back in. After that, I went back and turn the phone on again, and it won't work. Can anyone tell me what's happening ? I have no idea. I even took the LCD off and put it back on again, but it won't turn on. Only a dark blue screen, but no apps or anything appeared. Thanks everyone.