Did your LW stop connecting, or did your downloads stop connecting?
How many green connection bars do you see? If you only have the first green bar, do this test & see what result you get
http://www3.limewire.com:6346

Do you see the firewall icon (brick wall)? Make sure that you're only using 1 firewall that's configured properly. You'll find a link for firewall config in the thread below. You'll also find lots of helpful info about configuring modems/routers. If you're still stuck, post back with your details. The thread will explain what info we need
Connection problems? Check here first!