The Digital Editions folder still exists in My Documents, Does it still have the various books in it, as .epub files?
What happens if you try to open one of the books in ADE? (ctrl-O and navigate to book, or drag-drop book from Explorer onto ADE)
You should havea file 'C:\Users\<username>\Documents\My Digital Editions\manifest.xml'
which contains information about books and shelves. Is that there?