WD My Book 1110 Lost Drive? Won't mount, Says Unallocated in the Disk Management

WD External Drives External Drives for PC
3

I did that. I used a few. One did not recover the real file documents I needed. I pulled the photos ok, but the graphic designs in AI and Coreldraw was not pulled and some that managed to get reovereed were trunked and openned as blank documents with no content. 

Any thought from here?