This is useful to use one instance of notepad++ across your main os and your VM. How to make things portable is on their FAQ but I can't find it anymore.
To prevent re-opening of files, Settings, Preferences, MISC. and uncheck Remember current session for next launch.
Did not need the extra steps just used plugin manager and chose XML Tools - http://geek.sylvainw.com/2010/03/28/using-notepad-to-quickly-format-xml/