(What I meant about the interchangable drives, which I should have made more clear, was that I have a choice between having a combo of CD/DVD drive with either a floppy, a subwoofer, or a number-key pad.)
The computer came with Windows XP.
Basically what I did to slove this problem was taking out the subwoofer, and inserting the floppy disk drive in its place. When I restarted the computer, the error message disappeared. I then plugged the subwoofer back in place, and the error message did not come back. Now.... I don't understand WHY exactly that worked, but I'm happy it did.
Thank you both for trying to give some suggestions, and sorry for wasting your time.