i bought the limitedetion of crysis 2.It gave me a key with the form of XXXX-XXXX-XXXX-XXXX,But when i want to play multiplayers games,the game expect me to give him a key with the form of XXXX-XXXX-XXXX-XXXX-XXXX,is the key on the instruction book??

On limited edition u found 2 codes, one for unlock unlimeted contents and one for the game, use that than are back of the game document.