CoD4 installation files

Hello, guys! Where can I download original licensed CoD4 game on english version?

Steam or buy the CD (Often on 50% sale on steam)
Careful buying cd key online, some will just be the keycode and not include the game files.

Or you can search some cod4 community websites, maybe they provide a link to download the english version

I have russian license disk of the game with a license code) I just want to play in english version of the game))