Question External HD not shown in Disk Management

[Novel8]

Like I said in Subject title, but it does show up in Device Manager under Disk drives. Also it does not show up in windows explorer of win 7. How can i possibly use this hd otherwise?

 

[USAFRet]

Like I said in Subject title, but it does show up in Device Manager under Disk drives. How can i possibly use this hd otherwise?

Need MUCH more details.
What drive, how is it connected, etc, etc.