Mac, I'm plumb out of ideas. If it isn't a bad drive I'll eat my hat...But I hope that you won't hold me to that statement, 'cuz I've been wrong in the past!
It was good to hear that you could reformat the drive using Apple software. I believe that my reformatting problem was related to the drive being an OEM, which precluded going back to Apple after using HDT. I wish that I could remember where I ran across the info (it was over five years ago...) but all I know is that I can't do what you did.