So you configured your xp firewall using these instructions?: http://www.limewire.com/english/content/firewalls.shtml

Your modem is a usb. The only point I'd make about usb modems is that they can be inconsistent from what I've read. They draw power form the comp & also utilise the computer's processor. But I doubt this has anything to do with your present connection issue.

Have you seen this: http://www.gnutellaforums.com/showth...threadid=23895

Also try this: Force IP instructions & sample image