My 2007 navigation system stopped working. At first it was completly blank, now I can use the radio and air most of the time. I was getting a disc error and to consult dealer but now I cant get past the black screen that shows the Nav logo when I first start the car. Also while Im driving the error message will say either contact your local dealer or that I must start the ac after the car is started but this is while im driving.
Can someone please help me with these two questions?

1). Does my nav affect my AC? Becuase as soon as this starting happening my ac is not cold at all and will sometimes be colder on the passanger side but warm on the driver side.

2). If I buy a new DVD do you think it will fix my problem?

Thanks
Dave