Someone may have accidentally put tablet into safe mode or power off mode.. You may need to open the back up and remove the battery to allow any residual power to drain away. I left my battery out for 30 minutes as I was told. Seems one of the kids put tablet into power off mode meaning I couldn't turn it on.. At first I thought the battery was gone. But using a voltage reader it showed the battery was at a healthy 4.30V. Back to Google I went.. Then I found this idea and voila.,