Error message whe signing in to Instant Messenger

Lately when I try to sign in to Windows IM I receive the following error
message:

"Signing in to windows live messenger failed because the service is
temporarily unavailable. please try again later. error code: 80040154"

I checked the Service on:
http://support.live.com/networkstatusres
ults.aspx?ProductNum=100&ProductLocI d=2452
and it states:

"The service is available; there are no known network issues at this time."

I recently upgraded my Antivirus software "Norton Internet Security, 2007"
and this is when I started having trouble.

I disabled my firewall and tried to sign in. I got the same error message.
How can we fix this?
Thank you very much...