MSN Video's disconnects my internet connection

I'm using Windows XP Media Edition. Connected to the internet through a
Linksys router, and have Norton Internet Security installed. My problem is,
that when I go to some streaming video sites, such as MSN video, I get
disconnected from the internet. Really I'm connected, but explorer won't
open any pages. My Outlook won't connect for checking email either. I have
to unplug all of them, then reconnect. Some setting is not working properly
for me. Wonder if anyone could help me out.