Click Settings then click General. Click the Software and Reset tab, then click Reset under Factory Reset.
Click Begin Reset.
PERFORM AN ALTERNATE RESET: With the device turned on, press and hold the power button for at least 15 seconds into Factory Reset Mode. You will see a screen showing "Shutting down". Note: Be sure to hold the Button for at least 15 seconds. If you do not hold the power button long enough, you will turn off the device instead.
"Continue holding Power button to reset all setting to factory default" will display. Be sure to hold the button through this screen. Note: After this "Resetting Device. Please do not power off will display" and Factory reset will complete.