I don't have space for the sims 2

Hello,

HI, I have a problem with my computer installing the Sims 2; this is not an expansion pack. I can only get passed putting in the activation code for the game, but that's it. The original Sims 2 is a four disk set up, plus, I have to have the very first sims installed as well. How do I make space for both? The first Sims is only a one disk set up. What do I have to delete in order to make enough room for the first Sims and then the Sims 2? Please I need help!!!!!!!!!