Well, now the problem has returned, and for the life of me, I can't remember how I fixed it the first time! I'll do what RealBeast recommended.
My wife has a Mac PowerBook Pro. When you slip a blank CD or DVD in, it displays the disk icon as either a CD or DVD. Windows won't do that (unless 7 changed it). So when you've got kids who like to mess with your blank disks, and you don't know if you've got a CD, DVD, or a coaster, it's a real PITA.