Let me revive this ancient thread and correct those who answer but have no idea what they are talking about. This isn't a bad disk and the disk isn't dirty. The navigation unit is toasted. They do this. If you want to fix the thing, a dab of grease must be applied to the DVD clamp. You have to disassemble the unit to do this, which includes disconnecting ribbon cables. Brave? If you've changed an Iphone screen you can do this. Buy the Service Bulletin for the unit on a place like "Manualsparadise.com" and it will tell you what you need to know. The unit is made by Pioneer and has a Pioneer number that begins with AVIC-.
It would really be nice if folks who had no idea of a remedy stopped posting their nonsense: "remove negative battery cable..."
