The navigation screen is blank. when you open the door, the screen lights blank white. when you start the car, there are some horizontal lines that go through the screen top to bottom for a few seconds, but then nothing. I checked all the fuses and put the CD back in. Is this something I have to have to get the system to reset? I checked the manual and couldn't find any codes to use. Or is this just a symptom of a larger problem with the navigation system/computer? Thanks for your time.