windows live messenger doesnt work.

hi,
i downloaded latest version of WLM and although i can login and see all contacts, when i send messages, they do not receive them. Ive run the connection troubleshooter and it says i have a problem with key ports. When i click repair the problem persists. Also in the TCP box it says cannot connect to the service. i am also unable to ping messenger.msn.com. yes i can ping www.google.com.au also my firewall is the built in XP SP2 firewall which i have turned off. I ran a tracert for messenger.msn.com and it seemd to drop out on the 11th hop