Can i play ESF using CS:CZ? plz help

My brother recently bought a video card and it came with a copy of counter-strike: condition zero. And since the section ABOUT in the main page says that i can play esf with a copy of cs, i thought that i could use cs:cz. but it seems that esf i wont accept it. Esf doesnt accepts it at all or im doing something wrong??

i assume that you're also able to play the original half-life? through steam..
you have to play the original half-life first then you can install...this isis what i got out the installation process...

nope

you cannot play anything apart from cs and cz with a cz cd key.

so i'm afraid you can't play esf with cz

....oh... ok. thanks

Sorry I just want ask what is cz is it the cdkey for half life?

no, its the cd key for condition zero