Outlook won't open, multiple outlook.exe running in processes?!

Hello-
I have been having an ongoing problem with outlook 2002. (windows XP)- After my computer is on for awhile, outlook will not open. In task manager I see multiple instances of outlook.exe running, although the application itself is not list as running under the applications tab. I have to reboot, and then when I click outlook it asks if I want to start in safe mode as it failed to open properly last time. I have done the "detect and repair",
created a new user etc...
My other office programs are working fine- could this be related to Norton Internet Security(2003)?
Thanks for any help!
Ariel