Yesterday I installed some .apk files (i forgot what exactly they are but seems some google apps like vending.apk and others) downloaded from the internet. The tablet kept rebooting, even I use that reset hole to reset. What should I do? I want to do factory reset! But how? HELP! My tablet is not rooted. FIXED!!! I switched it off and then turn it on by holding vol- and power buttons to enter fastboot mode. Connect the tablet to PC (with ADB tools installed). Use command to wipe everything and factory reset. Reboot and it's back to normal!!!