Nook tab s2 restarting itself

[AC Question]

My nook keeps shutting itself off and restarting when in sleep mode. Won't do it if it's being used. It restarted itself so many times the other night the battery died. Battery life is good, charging is good, hard reset heloped for a few hours. Now it won't even go to sleep, after a few minutes it powers itself off completely and about an hour later will restart until the batter is drained (literally hours on end of restarting)