Limewire is simply a client on the Gnutella network. If it suddenly stopped working for you, then it's not Limewire that's the problem. It's something in your computer or network.

I would try downloading another Gnutella client and see if you still have a problem, if you do then it's likely your network.

If you don't, then it's likely that your Limewire install is foobar somewhere. Reinstall it.