Panasonic SC-DT100 System "dvd player troubleshooting code" Questions

dvd player is ,and what brand it might be ,their are many variables to this answer , first of all if your volume works and the rest of the buttons do,nt ,I have to wonder if we are talking about a dvd

...DVD player, turn it upside down and gently shake it (this will remove any dirt or dust that could be preventing your optical pickup from working properly) Hook everything back up and try it again. ...

dvd player won't open the door where i put dvd's and cd's won't open and the on screen display simply states " locked" i have never seen this happen and i have no idea how it happened,i cam home, went

...DVD with the improper Region Code numbers is loaded, ?REGION ERR? appears on the display and playback will not start. ?CONSUMERS SHOULD NOTE THAT NOT ALL HIGH DEFINITION TELEVISION SETS ARE FULLY ...