Sharepoint Site - "access denied"

Incidentally, we have also had users unable to log in to SharePoint sites — the browser would say something like "access denied" without even giving them a chance to login — and found that the cause was essentially the same problem as the post below: cached incorrect username/password combinations.

Once again, simply delete the affected sites' entry from the Managed Passwords list as described in that post. Also make sure that any SharePoint sites you use are in your "trusted sites" list under IE's Internet Options window.