You either need a newer version of Daemon tools (4.08 is out now) or as affasd said, a no-cd crack. Since you don't have an iso image to mount, a no-cd crack is probably the trick. The download probably came with one, look for a folder called crack, or hack, or nocd or something like that. If not, hit emule or something to get one.

Go to the actual working folder of the game, probably in the "program files" folder and rename the main executable from "gamename.exe" to "gamename.backup" and copy the new "gamename.exe" to the folder.

That should be all you need. If not let me know and I'll tell you how to do the Daemon tools way.