Have a peek inside.
Unplug all the cables and turn the board over. Undo the 6 Phillips screws on the bottom of the board.
Lif the bottom panel up gently. Disconnect the fan's power supply cable and set the bottom aside.
Locate the system EPROM's (there's four large chips all together). Check to make sure they haven't worked their way loose out of the sockets. Also locate the PSEUDO and GODOT chips (they're smaller, and also socketed) and check for looseness. You can push any chips back in with your fingers (carefully!)
Put the bottom panel back on (don't forget to plug the fan back in!) and screw the thing together again. BE CAREFUL RE-TIGHTENING THE SCREWS ON THE CASE! The bottom panel is plastic, and cracks easily.
Do a hard reset and check the display.
If no luck, you're going to have to take it in.
Steve Martin
Ward Music