If you have, or can borrow, another USB-miniUSB cord, from a camera or phone, try that. It could just be a cord problem.
In MSC mode, two drives should show up on your PC. One is the Clip, the other–Removable Disc–is the card slot. If there’s no card in the card slot then your PC could get very confused. Are you sure you are not trying to format an empty card slot?
