Use Atlantis
Atlantis Word Processor
I suggest you make word convert the file to .rft format by doing a save as and selecting that file type.
then import it into Atlantis or open it there and do your editing
then do
save special and then
save as ebook
that will give you an epub file which can open on nook
to get it into kindle though your best bet is to make an .html file and then use MobiCreator free software to convert that to a kindle file.