It says I have Zero KB available. This is my first mac, I have just got it today and I don't really have a clue what I am doing. Any help would be much appreciated!
Are you installing from a CD or DVD?
If so, be sure you select your hard drive as the destination for the program in the installer's screens. The installer may be defaulting to selecting its own disk as the destination - and, since a CD or DVD can not be written to, it wil show no space available.
Leanne,
We need more information such as what version of OS X you are using . You can find that by clicking the Apple Symbol in the upper left of your screen and choosing About this Mac. Also it would be helpful to us if we knew how you installed Sims 3, did you download it (if so from where) or use a DVD. Also are you getting that message in the game? In short the more information you provide the easier it is to troubleshoot.
Finally I'd strongly recommend book marking and studying:
Can't install the sims 3
