I had the exact issue and panicked because I didn't do a backup of my fiancé's phone before I did the screen replacement. When I plugged in the phone to my laptop, it appeared as a connected device and showed all the correct information related to the phone. The screen went black, and only made a repeating charging beep and a vibration when I would turn the sound on and off. Below are the steps that I took: -Removed the bottom 2 screws -Elevated the screen (did not detach the screen) -Removed the shield that connects the battery to the main board -Disconnected the battery -Held down the power button at the top of the phone to remove any remaining power -Reconnected the battery -Placed the shield back -Reconnected the screen to the phone -Powered on to test and BOOM!! It was working like new and immediately did a full backup. I really hope this helps you with your issue.