I have 1 terrabyte and its full by 500 gigabyte

i have a dane elec speaky hdmi 1 terrabyte fat32 system when i fill this with movies it gives by 500 gigabyte its full but i have 1 terrabyte on this multimedia so i formate it too ntfs system too upgrade it too 1 terrabyte it works but i couldn t see nothing on tv so i looked and saw this system works only on fat32 which was not wise because it works only on fat32 so i returned it too fat32 and still it give full by 500 gigabyte now my question is how must i do it too formate this fat32 from 500 gigabyte too one terrabyte