Originally Posted by Clamchowder
I left it alone for a bit and when I came back to it it had an arrow in the middle of the screen and lat/long in the top corner
Did the lat/long correspond to where your boat was?
We're a long way from the sea, too. If I turn my 551S on at home it shows the icon for "you are here" and the lat/long but no map, because, there's no sea. So I think a blank screen is the norm if there's no sea to show.
Can't explain the buttons, though, unless the random button pushing caused a hissy-fit.