Oldfield since it only happened at the change over it is unlikely your ISP but you might want to confirm that with them. You should clear your cookies, and deleted any stored password/username on your PC. Also you might like to check your security settings, to do this open up Control Panel, from there select Action Center and see if you can change your personal settings via this route. This information is supplied by other mods, let us know how you get on and I will see if they have any further suggestions.