Sims 3 UltraISO help?

So I have all the Sims 3 Files on my computer & everything but I lost the disk:/ When I try & launch the game, it gives me a message saying to please put the game CD in the CD drive in order to play the game. I heard you can use some programs like UltraISO or Alcohol to convert convert the game into a virtual disk/drive? I downloaded UltraISO but I have no idea what to extract exactly or anything! I've tried reasearching on how to but no instructions are really clear enough for me. HELP! And thank you in advance :)