Two dueling hard drives? 1.5 TB WD My Book Essential

I have two 1.5TB WD “My Book Essential” hard drives. My computer seems to think they are the same drive and won’t read them at the same time. I get no errors when they are both plugged in, the second one just won’t read. 

They are both present in device manager but not in Disk Management…

I have tried assigning unique (unused) drive letters, but the computer still thinks it is the same drive (I.e. I plug one in, assign it “X” and then unplug it. I plug the second one in, it shows up as “X” so I assign it “Q.” I unplug it, plug the first one in again and it shows up as “Q”.)

Does any of that make sense? Am I going insane? Am I missing something really simple?

Can anyone help?

Thank you!!!

See if this works see post 11.