Can't post to a site that requires authentication

From: Bryce (Bryce_at_discussions.microsoft.com)
Date: 12/06/04 

Date: Mon, 6 Dec 2004 07:19:01 -0800

I cannot access websites that require authentication (username/password).
When I go to the log in page of a website I get the cannot display this page
error. I think this is a result of downloading the service pack 2 update.
Any advice? I can't find a fix. Many thanks. 

-- 
-Bryce