Just press and continue to hold bothe the quit and route buttons simultaneously. Then with your third hand press the on button. From my memory, I let go of all three when the first page appeared (I think the "agree" page). As I recall, nothing magic seems to happen, but it's an internal reset. My unit simply started functioning after that.
One more thought... I just remembered that I had replaced the internal memory battery. That is located inside the unit and is solder in. Not a big deal, but I heard that can cause what your seeing because the unit has no idea where you are. So if the reset doesn't work, next I'd try the internal battery. For me though, the reset was it.