Check the contact when flipping the screen back down, those two contact circles need to make a proper connection once the screen is put back on, there are two leaf clips that can be damaged opening the phone. Hope this was helpful .
What I have come to find out is that the click wheel connector and ribbon cable had a loose connection from the adhesive breaking down. The ribbon cable has a sloppy fit on the connector and am speculating that the connection has a sloppy fit and did not make a full connection, but I have 3 more with the same issue and find that ironic. Thanks for the feedback.
I had come across this issue in the past, so process of elimination. Does the phone run hot? Has the phone been dropped at all that may have jarred the components inside? Because the phone runs warm may interfere with other components? Possible digitizer needs replacement ( worst case scenario) You will not get any response with a dead screan Lastly- battery replacement. I cannot imagine a software shut down. Good luck