Hi there Smankusors,
That is unpleasant.
🙁
Did you have any issues with the drive before putting it into enclosure?
My suggestion would be to connect the drive internally to a desktop machine. That way you will rule out a possible enclosure related problem. If you can't access the drive right away, you can give the partition/data recovery tool one more try.
In case the issue persists, you need to go to BIOS and see if the drive is recognized as having 0.50 KB. If this is the case, then I believe the drive has some internal flaw and you will need to contact a data recovery company if the data stored on the drive is really important.
WD's Data Recovery Partners:
http://products.wdc.com/support/kb.ashx?id=g9YMIs
Let me know how this goes,
D_Know_WD