LCD Display Replacement / Power issue

Alright, so I opened my iphone 5S to replace the LCD display and forgot about having to disconnect the home button ribbon cable. I ended up replacing the screen and reassembled the phone without a working home button. After having the phone working for 30 seconds, I powered the phone down and reopened it from the top with the mini suction cup. I pulled a little too hard and now the phone will not power on (plugged into computer and emailed myself and nothing) I disassembled/reassembled the entire phone again and found all 3 ribbon cables intact on both ends /no noticeable damage. I tried disconnecting the battery and reconnecting as well. Any idea of the problem? and Is it possible for an iphone to be on and receive calls without a connected display (ripped ribbon cable)