can i use conter strike condiition zero key if i already used it for conter strike

[saiyan fusion]

can i use a conter strike key if i already used the key for the game itself somone plz repley

 

[Grega]

You could use it

but ESF dosent work with CZ sorry

You nead HL1 or CS retail

I repeat ESF does NOT work with Condition Zero or Source youu nead Half Life 1 or Counter Strike 1.6 retail.