Word doesn't recognize existing citations

Hello,

I am working on a very long document with a large amount of citations.  Multiple chapters, bibliographies for each section.  While editing, I have found that Word 2010 no longer recognizes the hundreds of citations I have already entered.  It adds new citations as if I am just starting the bibliography.  Right clicking to edit an existing citation doesn’t show it in the list.  Converting to unformatted doesn’t change any of the existing citations.  I still have the bibliographies of the existing citations, but they do not update.  They don’t seem to even be recognized by Word/Endnote at all.  If anyone has any suggestions, I would be very grateful.  I do not have time to redo all 500+ references in the text.  No idea how long this problem has been present, and I have dozens of previous versions.

Thanks,

CF.