you need the NO-CD crack. it's usually a file that you replace in the existing game directory, eg. c:/program files/(game)
google NO CD crack for that game. if you downloaded it from the pirate bay, chances are there is already a crack on the disc. using magic iso, right click on the cd and choose open in explorer, look for a crack folder. And in the future, be sure to follow all installation directions that come with your download. There's usually a readme file attached. FOLLOW DIRECTIONS