I am by no means a computer wiz.. but I am having just about the same problem you are.. except that i have a strong internet connection I use DSL as my internet provider.. but for some reason lw says I am behind a firewall, but I have no firewalls..
But to answer your question... the first thing I would do is contact your internet provider, maybe they are having problems of their own not even related to lw..
good luck to ya,
tigercubb