My navigation screen either stays completely black where will appear with vertical black and white flashing lines. It never goes to the start up screen and I cannot figure out what's wrong. I've tried disconnecting the battery terminals and reconnecting them, check the disk, and a few other things but nothing seems to work. Any ideas?

 

I was having the same issue, now my screen just remains black at all times. I have tried a few of the same things that you have mentioned, what other things have you tried?

 

it's dead jim.