I didn't think Windows Defender included a firewall (thought it was antispyware). You can use a software firewall, just make sure that it's allowing LW.
User Cant Connect - LimeWire

Try port forwarding for your Netgear, the instructions are here.
Port Forwarding for the Netgear CG814WGv2
Don't forget to set up a static IP address first. LW's listening port, port in the 'manual port forward' box & port forwarded within the router setup should all be the same number