Volume Serial Number is a serial number assigned by the Operating System to a disk volume. Disk Serial Number Changer helps you to modify your disk drive's Volume Serial Number (not hard disk's physical serial which you can find at back of your hard disk), the format of Volume Serial Number is: XXXX-XXXX (X - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F).