I am getting a little frustrated.  I have tried everything that you are suggesting, to clear the cache have done it multiple times.  I am thinking that it is an Outlook problem, not our individual PC's.  When I go to the People category, there is nothing, nothing when I click on "To:" when writing a new email.  So....I am hoping that someone can get this resolved for all of us.  There are no errors coming up, there are just no contacts listed.