This might help!
I had exactly the same problem. I tried the system / prog button reset but that did not work.
I removed the upper plate, then i removed a silver plate with 3 screws (cant miss it)
I removed the cable from the display on both sides (important! If you disconnect only the display side it wont work, dont ask me why). Then i placed the cable back after a few secs and like a miracle the display worked again! No strange signs anymore and works like new.
The picture above shows wich cable to disconnect.
I really like to know if this is helpfull for others.
Gr, Richie