External hard drive(WD1600d032) no longer shows up in My Computer

I have a wd1600d032 external drive which has been working perfectly over the last 7 years.   As of recent it is no longer showing up in my computer (Dell Laptop  XP os).

   The device has power. 

   Attempted using new usb cables

   Rebooted numerious times

   The issue still occurs when I try another XP or Windows 8 laptop.

  

   What I did notice in device manger I can see under Disks, WD External USB Device but under USB it is saying unknown  device.

Any ideas what to try next?

I am having the same experience on a Mac.  Help!! Is there a down load available. 

Hello to all,

Have you guys tried to run a test on the unit using a DLG Tool?

Please see the following link for instructions.

http://wdc.custhelp.com/app/answers/detail/a_id/940/session/L3RpbWUvMTM5OTQ5MTYwNC9zaWQvNXA4NmRIVGw%3D

for some reason mine has stopped showing up on my mac and my windows pc. i have had it for years and it has always worked just fine until a week ago. doesn’t show up on disk utility or device manager. tried all new chords nothing will work. it powers up so it knows it’s plugged into something but nothing will read it. help please.