Error 22

Are you using a computer running Windows? If so, you can open Windows' Device Manager, go the disc drives list, right-click on the affected disc and choose "enable". Sometimes Windows might automatically disable a hard disc if it detects a physical problem with the drive or another other technical issue. Code 22 errors can also be caused by a bad driver or even a loose connection.

If the computer is able to read the hard disc again I'd back up any valuable data on it (if that hasn't already been done).