I started my tablet and it took forever. I kept getting a play store error and I couldnt get my wifi on. The play store error kept coming back. I thought restarting might work. Now I cant get it to boot fully? I have tried to boot into recovery. holding down volume down key and then power for 15 seconds..didnt work. held down volume down then volume up and then power..didnt work. what should be my next try?