I've installed Vista (Build 6000) and Windows Live Messenger (Build
8.0.0812) and cannot get Messenger to sign in. It gives the same error every
time - 81000306. This is a fresh & clean Vista install and the local
firewall is disabled but there is a firewall on our router. Since all of our
XP SP2 users have no problem with the same version of Messenger, I am
guessing that there is something different about the way Vista works with
our router. My IT guy is reluctant to change anything at this stage unless I
can make specific requests about what needs to change.

Any ideas what to change that might fix this? Is this a known
incompatibility with Vista and Messenger?

Thanks.