j'ai cherché de mon coté et j'ai trouvé la réponse à ma question donc j'en fait profiter ceux qui ont ou auront le même problème que moi.
If you don't have enough space on drive C:, you can't install the game via the autostart based setup. In this case, please use the individual version's setup programs :
You find the in these places:
Medieval II : Disc 1, in folder \m2tw\Disk1
Update2: Disc 2, in folder \Update2\
Update3: Disc 2, in folder \Update3\
AddOn Americas: Disc 2, in folder \americas\
AddOn Britannia: Disc 2, in folder \britannia\
AddOn Crusades: Disc 2, im Ordner \crusades\
AddOn Teutonic: Disc 2, in folder \teutonic\
source:http://shoguntotalwar.yuku.com/topic/29207/
t/t-install-Total-War-II-Gold---space--C-Solution-
use-custom.html