There's a chance your school blocked LW after they detected it being used. Strange you could connect thru port 6346 one moment but can't the next. For Norton Firewall, see Configuring Norton Internet Security

To disable your XP firewall, see http://www.gnutellaforums.com/showth...842#post178842 as there's more than one technique depending on how you're set up.

My guess is the problem is your firewall. But if you set things up & still problems then see below. Last thing to try would be a proxy. But proxies are time consuming to set up & find one that works.

What you could try doing is, changing the port LW uses. Go to LW's menu bar, Tools>Options>Advanced>Firewalls & change the option from upnp to manual port forwarding & change the port from 6346 to something like 80 or 64049 or 34599 for example. But you'd need to disconnect from the file menu & try again after such a change. You'd also need to change the port options in your firewall.