You need to give a bit more info here!
Tell us what fixes you've tried that didn't work.

Did you double check your Win firewall configuration? How did you have your router set up when LW was working... did you have UPnP enabled or were you port forwarding? Have you gone back through your router config again & double checked things? Do you see the firewall icon? Does the port test work? Do you have any green connection bars at all? Are you getting any error messages?

What are your details (as per post #2)?