thanks 🙂
Therefore, you’ll need a brand new (unopened) copy of the game to create a new account to play FFXI, as the registration codes are linked to your payment option (for instance, if you create new extra characters you’ll need to enter your registration code for FFXI).
If you bought it from a friend, then it’s likely that the codes have already been used and linked to his character and cannot be re-used by you. Really, sell it back to him and buy a new copy of the game, as it’s the only way you can play FFXI.