I occasionally have had a similar problem (I posted about it a couple of weeks ago). Sometimes I can not get the 770 to turn on. Sometimes multiple button presses works. Other times I have to just leave it alone for an hour, then it starts right up. I don't think it is the button itself. It almost seems as if the tablet just locks up and fails to respond. I have tried removing the battery, then reinserting and trying to boot, but that has no effect. It only happens to me on rare occasions now, and my hope is that the new firmware will make this strange behavior go away.