When you click on the picture of the monitor and select Properties in CCC, what info does it give you about the phantom monitor?
EDIT: Just thought of something... Have you by chance hooked this pc to a television? I remember having a "remnant" monitor in CCC after hooking my pc (the one with the ATI HD 2xxx card) to a television once. I had connected it via the S-Vid out on the card. And again, to repeat myself, to the best of my recollection, I removed it by disabling it.
Doesn't sound like this is too much help, though.
I'll post back if I remember something or if I can recreate it (it was in Vista, though)