Why won't Sims 2 work?

Ok it took like, forever to install it yesterday (I have Sims 2 Deluxe if this makes a difference), then it gave me an error about DIrect x 9.0. I was like what the????? because it works on a different computer I use at a relative's house. They have Windows XP or Vista but I don't really know the difference. My computer at home that I am on right now is Windows Vista Home Premium. Anyway, I looked online and tried the compatibility mode fix. It worked, but then it closed after i clicked on the cheat box at the top of the screen. Now, it will usually say the application has crashed, but sometimes it says something about Direct x 9.0. I don't understand!!!