I have the Advent HR9000PKG 7" LCD Monitors and Build-In DVD Players for Rear Seat Entertainment installed in my car. One of the DVD players stats "Bad Disc" when it is turned on and will not play a movie. I have had this setup for 1 year and had numerous problems throughout the year. Can you please tell me what to try? The other DVD player works just fine. The one in question will show the DVD that is playing in the other player but not in its own player. Thanks.