i got it from my friend... he said he downloaded it from the internet... the files cs16full_v6.exe and the size is 278,834 kb

i tried running the game and type version... and this is what i get :

] version
Protocol version 47
Exe version 1.1.2.3 (cstrike)
Exe build: 13:13:21 Jan 13 2004 (2637)

maybe it's a different version than the usual steam ??