Garmin nüvi GPS showing "PRESS DOT" when switched-on?

I suggest, first you go outside so that your nüvi can find satellite, and then see if you can actually press the dot using a pen or pencil (with the plastic tip, if possible). You should be asked to do this a number of times (5 times usually) until the screen is calibrated. Be as accurate as you can. 

If you still get no response then try a hard reset.