You don't state your Outlook version, but the Calendar view of the
Navigation Pane in Outlook 2003 will always show all the calendar folders in
your mail profile, with check boxes to the left of their names so you can
specify which you want displayed in the view.  At least, that's how it works
for me.  You should be able to uncheck the box to suppress the calendar you
don't want.  You can also remove the Archive folders from the folder list.
Right-click their root and choose Close.