You may have to delete or rename your outcmd.dat file while Outlook is
closed -- it holds toolbar customizations and when it gets corrupted you'll
have trouble with your toolbars and menus.  Close Outlook, search for the
file (it may be in a hidden folder), and rename it to outcmd.old.  When you
reopen Outlook it will rebuild the default toolbars and menus.
Unfortunately this means any toolbar customizations you made before will be
lost -- but your toolbars should behave now.  If you recustomize them, save
a backup of the new outcmd.dat file so you can restore it if you ever run
into this issue again.