Yes new HDD with win 8.1 works fine, except I have not installed Drivers as of yet. Original drive worked before head got stuck. Was able to gently edge it back off disc while rotating disc CCW. Could it be that installation of new HDD with win 8.1 has left information on computer that even though drive has been removed is conflicting with original drive and must be first removed?
Pardon my lack of proper computer vocabulary.
I tried all the things listed, except the real complicated stuff. Turning off and on and off and on and off and on and off and on, no results. Finally noticed that as I closed the lid I saw a flicker of light. Turned out I have this exact problem, but it's nothing more than a bad circuit or worn wire. The screen works fine as long as the lid is only open about 6 in, so at least I can use it until I find the right diagram or information on how to fix the connection.