Answered you by pm. I might have been wrong about the modem being your issue.

Recheck norton's settings.

If it happens again, you could try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)

Make sure your Java is up to date. You should have at least Java 1.5. You can check by going to LW's menu Help>About LW... Will show both LW & Java version. You might even consider Java 1.6 beta which has had very good reports; http://java.sun.com/javase/6/download.jsp JRE "Offline" version which is a 15.72 MB downld. But that's up to you.

Sometimes the brick wall on the icon can show when you 1st open LW, but although it should disappear immediately, sometimes it may last for up to 15 mins or so for some people. I don't know why this happens. I'd have thought UPnP problems. But probably a reboot might fix it.