I am about to lose my mind over this.  Out of the blue, my Outlook program
started periodically "stacking" up - not closing.  If I go into the
application manager, Outlook might be running four times.  When it starts
doing this, I no longer get e-mails, I'll get two notifications (envelopes or
brief preview at the bottom of the screen).  Once that occurs, the only way I
could get Outlook to start again was by rebooting.  I have now found that
most of the time, I can get it to correct through the applications manager,
by ending all but the main outlook.  I know the main one because it is the
largest file.  

Has anyone run into this before?  When I tried to reload or repair it from
my disc, I get an error stating "the installation source for this product is
not available.  Verify that the source exists and that you can access it"
which I've done.

Our IT dept is puzzled over this problem as well.

Thanks for any input.