Invalid media or Track 0 bad - disk unusable.
The disk may be unusable, or you may be trying to format the disk to an incorrect format.
Make sure you are formatting the correct density. For example, you cannot format a double-density disk as a high-density disk. If you continue to get this message, the disk may have bad sectors near the beginning of the disk. The Format command can accommodate defective sectors on the disk, except those near the beginning. If the disk is a floppy disk, use another disk. If the disk is a hard disk, contact your hardware vendor.