My Book Essential problem

I have a problem with My Book Essential 2TB. I bought it in August of 2012 and used it as backup for my home PC. My computer recently had to be reformatted because of a Windows software issue, and when I plugged the MyBook back in, it comes up as a drive, but only has a folder labeled WD Smartware.swstor, and when I open it, it says its empty. I can scan the folder with my Norton software and it shows there are 45,000 files on it and 339GB of data saved. Any help would be greatly appreciated.

Did you try checking show hidden files? Sometimes you need to do another backup see this post