Hi,

Go to Home > Settings > Personal > Backup and Reset and see if there is an option there to do a factory restore or reset.

Be aware that this will erase all your user data and downloaded apps. It will restore the tablet to a factory default condition.

Ensure that the battery is fully charged before performing the reset and that the external SD card (if any installed) is removed. Do not perform the reset with the charger connected.

Hopefully this is of some help.