Just purchase from my local bike shop today and like others it's dead. No charge, no charging light, nothing after holding power button for 30 sec. Disappointing that I have to call Garmin support on this high end unit.
Maybe stating the obvious, but did you press the power button "deep" enough? I noticed that when I first turned on the unit that you have to press the button quite deep and hold it for a couple of seconds before the unit actually turns on.