[itimpi]

Did your backup of the library include everything in the calibre library folder? In particular did it include the metadata.db file that is at the top level of the calibre library folder that Calibre uses to store and track metadata?

If that is missing (as sounds like it might be from your post) then you may have to set up a new calibre library and re-add the books.

You also mentioned putting the new library in the same location as the program? If by this you mean put it in the Calibre2 folder under Program Files then you should not do this as under Windows 7 permissions may stop calibre having write access to the library in that location. The library should be somewhere else which has no such access restrictions.