C and D Drive

​ My 6000 came from the factory with a C and D hard disk drive. The harddrive is a 40gb. After my wife "used" it my orginal D drive is gone and now my DVD-CD drive has been re-named from E to D. My C drive is only showing 33 GB, which leads me to believe that the ~7 GB that was my D drive is still out there somewhere. Any ideas on how to get the D drive to show back up? ​