Your connection quality is in the red when you turn it on right? But you haven't actually lost your internet connection? Did you configure your XP firewalls & such:
http://www.limewire.com/english/content/firewalls.shtml
After opening LW, just leave it for some time. Then see how it is. If necessary, open it, go to Tools>Options>Connections & untick connect on startup & press Apply. Then go to File>Disconnect. Now wait some time. Then go to File>Connect & wait 10 mins to see how it is. Any chance of you trying this whilst the others are not using LW?
Whilst LW is closed do this simple test for us. Using your browser go here:
http://www3.limewire.com:6346/ The page should say ‘Test Page was a Success’. What happens when you go there?