You will need to perform a factory reset operation. For this, a paper clip is required. Turn off the tablet and unfold the paper clip then locate the very small hold on the side of the tablet. Insert the paper click and gently push and keep it there. While the tablet is off, press the Power button until the Android logo appears. Wait for the recovery to appear and select Wipe Data/Factory Reset then reboot the tablet and that's it. You will now have access to the tablet.