I'm pretty sure I have a problem now

The other day I plugged in my (what seemed to be functioning) hardrive into my mac book pro. Mind you i have not updated anything to mountain lion yet, so I wanted to back everything up. Suddenly when I connect it, a weird message pops up telling me to shut down my mac. I disconnect the harddrive, turn it on and it did the same again. I tried other computers and it shuts them down. Now that I know whats at fault, my questions are: A) When you send a product for replacement do they recover the data on the hardrive for you and put it on a new one? I have very important documents on this disc. B) Whats the communities experience with WD in terms of returning merchandise for a new product(of equal value)? 

P.S. My warranty is still there, so I am going to give them a phone call on Monday.

A) The hard drive is replaced but the information is not recovered.

B) Pretty good.

Check the link below for more info.