My Book WD5000 Not recognized

My OS Windows XP SP3 does not recognize “My Book Essential WD5000C032”.  Shown as unknown device unable to get OS to recognize it.  Any ideas on how to recapture data or get OS to recognize it.  

Well you need to test your drive using a different computer, also change the USB cable. If possible change the power adapter. If the drive is not been seen by the computer you will need professional assistance to recover the data.