Kindle not showing as Device

Recently acquired a Kindle v4, and have downloaded e-books from public library; these require conversion by ADE.  So that done, and according to all the instructions should be simple process to transfer to the Kindle.  But, when connected to the pc, although showing on File Explorer as connected to the pc, the Kindle is not showing as a Device in ADE, so not possible to tarnsfer.  Have deleted programs and re-installed etc etc, including downloading ADE 3.0 as well as 4.5 - with same results.  Looking at various things on-line to resolve, also downloaded Epubor Ultimate and Send To Kindle - which did the conversion and appeared to transfer the book - but only a portion of it (whether that has anything to do with Epubor being a trial version ....??)