Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I think there is a cure for the problem: I have heard of your problem with the Garmin device before this, several times.
If, along with 'Press Dot', the screen on your Garmin Zumo also shows a black dot, then don't press it with your finger.... press it with the plastic tip or nub of a pen, and do so about 5 or 8 times, and it will resume normal operation.
The 'Press dot' cycle appears to be a screen calibration that runs after the battery has been removed in some circumstances, or otherwise in response to a crisis in the device that has been recovered from. Or, in your case, the device just having received an update. (A major update, I would guess, but an update anyway.)
I hope this works for you. Please let me know (or at least, rate my answer, if what I suggest gets it working.) Thanks.