to format the mass memory
Hold the left shift key, the spacebar and the back key then the power key, *hold them until the device asks for the country etc.
And also, you need to turn your device off first, and then do as magamer described. But that will only format your C drive, to format your E drive go to menu/applications/office then tap file manager and go to E and then press options and you will a line of text that says "format mass memory" tap that and you're done.