Mail Security on multi-user Win2000

I was wondering how I can protect my email and serfing habits one my Win2000 pro machine from other users or people. Is there a way to be sure (relatively) that no one can access my Outlook Express account !? and also maybe keep other people from checking my serfing habits ? I guess it would all begin by setting individual users- having them all regular users, and me a admin. but how can I be sure they do not have access to passwords logged on locally ?

Thanks in advance