This guide shows where to locate and clean the lens that reads the discs. This may be necessary if the DVD Player isn't reading discs correctly. This will take delicate work in order not to damage the lens.
Remove four 7.5 mm Phillips screws on the both sides (2 on each side).
Remove five 7.5 mm Phillips screws on the back of the player.
Lift the top panel from the back and remove. It should come off without being forced. There is a lip near the front so you many need to slide the top panel back slightly to remove it.
Locate the lens on the disc drive.
Dip one end of a cotton swab in rubbing alcohol.
Lightly dab the swab on the lens. Be very gentle.
Let the lens dry before replacing the top plate of the DVD player.