please try inserting a pin key into a hole at the right side. insert it and wait till 10sec, remove it, and 3sec later try to on/off it again. i hope it will work for you, coz mine did that and success.
that happened to me too, now i cant open my iconia B1. when i checked my tablet yesterday morning its all black. so i think its empty batt. but when i charge it, cant open. i know when slept last last night my battery is 71%. what should i do? please help. i tried also to reset but its not working