Is there a way of having a macro run when Excel opens and another when
excel closes regardless of which workbook you are opening? I'm trying
to make is so users a prompted if the want to enable an Addin when
Excel opens and then automagically disable the macro when excel
closes. I know how to enable and disable the Addin, just not sure how
to do it on open and close.

I've been looking around the net a little and can't quite nail down
this answer.