What happens when you don't have any disk in the drive - does the computer boot up and allow you to display the OBC? I had/have a weird problem (see recent thread), and before it solved itself (hopefully not just temporarily), the computer would spend many minutes with black screen and occasional flashing horizontal white lines, then would boot up to just past the accept screen, then would lose it and go back to the black with flashing. This occurred after I managed to get the nav disk out of the drive, as well as when the disk was still in the drive. It seems like the problem may be temperature related - problem went away yesterday after car had been in sun all day and trunk was very warm. If you haven't already, let your trunk warm up and see if there's any change in results.

In the past I occasionally (every 6 months) had a boot problem, which I attributed to a bad nav disk, but now I'm not sure that it really was the disk. Might have been the same problem as just recently, but in the past it may have cured itself by the time i removed the disk, so removing the disk didn't actually cure the problem or affect the problem. Good luck.