10 Minuts Windows Messenger Live

Hi, I also got a problem.

When i use WLM (windows live messenger ) i got 10 minnuts to chat with my
friends, family you know what i mean. Then the internet will shut off.

The strange thing is, it is shutting internet in my whole house/network.
Cause we work by a modem.

I tried MSN 5 and this worked normally. Internet works normally, games work
normally, only windows live messenger isn't working normally. I tried to
change some setting with my firewalls but could'nt find something.

I am using Windows Firewall.

Someone that knows what to do?

(sorry for my bad english)