The Ried2, Welcome to the windows 7 forums
As you have already tried everything that has been proposed and suggested.
I recommend going to grc.com and checking out Spinrite. It is not cheap but I was able to recover
a similar hard disk problem to yours.
Steve Gibson who runs GRC.com is a well respected programmer and speaker. I recommend
that you give it a shot if you have the cash.
I don't have any financial interest in grc or it's products, just love them.