Outlook fails to load
 

Every second time I try to open Outlook it freezes up about 2 seconds into
loading it. It becomes unresponsive and then I have to cancel it. The next
time I open it, it asks me to open in safe mode because of the prior
problems, and it opens and functions fine but then the next time I go to open
it, it does the same thing freezes up during initialization with the Outlook
open page frozen and if you click on it, it goes to a blank page but still
with an Outlook title. Any ideas why? I am using 2 browsers, IE and
Firefox. I have Avast for antivirus and no spyware currently.
Any help would be appreciated. Thanks