Cd/Dvd disk

Hi, i have seen all the topics but i cant find a solution. I must have done something wrong but i don't know what. I downloaded a .iso file (not from this site but i hope you can help me). I tried to open it with some different programmes like deamon tools, anytoiso, toast, winrar and poweriso. Almost every program has a problem. With poweriso and winrar i get a typing screen, i found a code that should word so i tried it. it put the documents in an cd folder. daemontools anytoiso and toast say i should buy the full version. i can install the game though. So i did that. I have bought the sims 3 and have it on origin. When i open the sims 3 it opens pets directly. But when i try to start the game it says no cd found, please insert. i've tried to make an cd in the internal mac drive. But that didn't work either. It's the first time i try downloading a game so i need clear steps to understand. 

I really hope you can help me.