Sims 1 and Windows 7?

I have installed the entire series of The Sims 1 in the correct order on Windows 7. After installing Makin' Magic, I get the following error when I try to start the game: Please insert the correct CD-ROM, select OK and restart application. I am running the game in compatibility mode for Windows XP SP3 as an Administrator. It worked once, but hasn't since. Any ideas?