Thanks itimpi. I have checked and you are right about the redundant files, so I have deleted the Calibre library and re installed the Calibre software. So now I have a clean sheet.
When I click on add books it is looking for a file.
My books are all on CD.How do I get these books from the CD into my calibre?
When I bought my Nook it already had the books loaded , so this is the first time I have tried to load any books from a cd.
Sorry to be a pain.