I have the same problem too.
Its been like it for me since Wednesday afternoon
I'm running version 8.0.0812.00
I also have tried everything, including an uninstall/reinstall, clearing out
the cache, adding entries to the messenger hosts file - nada.
I'm not sure that its related to security updates - I haven't updated it for
a while - I've ignored the 'there is a new version available' nag pop-up for
weeks now - maybe thats the problem

. I can get on fine using web
messenger, and using an earlier version of WLM that I have installed on
another box (8.0.0792.00)