dont waste yr time. nothing works, all the advice i was given failed inc that bludy ctrl and f5.. just forget it, it´ll drive you mad, you´ve been warned
Is it showing under your My Profile page on AB?
When you go under My profile, Edit User Details is there a tick box saying whether it's active?
Have you tried logging out of AB, clearing teh cache on your browser (if IE use Tools, Internet options, Delete, delete..). then log back into AB.