I'm guessing you already clicked 'accept' on reformatting that drive. If you hit cancel when you saw those messages, there may still be a chance. I.E. Unplug it from the SATA port (shut it down first of course), then plug it in to a different port (or the same one again), then reboot. Or get an external enclosure for it and see if maybe the board that comes with the external drive tricks windows...
Sometimes you can use recovery utilities to recover that data, but those can be expensive. Others may have suggestions. If you reformatted though... sometimes the data image is still there it depends...
Keeping my fingers crossed for you. To others, ALWAYS back up your Daz stuff regularly. I've had a couple of 'WTF just happened' with my Daz install, and I can totally relate with how Sven is feeling right now. All that work... gone.
In my case, it turned out that my 'My Library' folder had been relocated elsewhere on my drive, so I was able to drag it back to where it belonged, but I hadn't done a backup on a couple of months so I was freaking out in the meantime.
At least you were able to upload your latest update before this happened, so that's something I guess...
I feel for ya man!