The Explorer cache isn't part of the problem here. Clearing the browser cache and/or reloading the page doesn't solve the problem. We've been through this before.

One thing that has helped in the past temporarily is clearing the cookies. Theoretically, this should be the same thing as hitting the "logout" link. I'm wondering, though, if the "logout" link does some more stuff on the server side that isn't done if you just locally clear your cookies. I'm thinking that's the difference.