This procedure will remove ALL data from the device's internal memory (e.g. music, pictures, videos, other user data). It is recommended to backup this data to a computer unless you are willing to lose it.
Data contained within the device's system memory (e.g. Google account, system and application data, application settings, downloaded applications, DRM licenses) will not be affected. To clear this data, a Factory data reset must be performed.
From the home screen, select Apps.
Select Settings (under Tools).
From the Internal memory section, select Erase internal memory.