I have been having major battery drain issues lately. Twice now I've left the Nook unplugged for a couple of hours and have found it completely shut down. Both times it started with a full charge & both times it needed to charge for a while before I could even power it up again. I checked the battery usage and the Android OS was the biggest drain at 39%. I just did a reboot and that changed to 14%. Before, I could leave it for a couple of days without charging. Now I can't go a couple of hours. I know I can go back to my previous backup, but I would prefer to try to figure out what the issue is. Any suggestions on where I should start?