How do you make Command and Conquer Generals become Command and Conquer General Zero Hour?

Answer 1

Command and Conquer: Generals Zero Hour is an expansion to Command and Conquer Generals. Install Command and Conquer: Generals then install the expansion pack to play the expansion.

In the menu where you select the game you want to play, the button that says "Command and Conquer Generals" should have a button directly below it that says something like "Command and Conquer Generals Zero Hour"

PS. this is for command and conquer: the first decade. Other wise you will need to download the separate game or buy a separate disk.