Gubru make sure you're not using the same port as the other computers using LW on your router. Consider port forwarding for just this one computer that's struggling.

hi_shobhit76 try varying your listening ports around in LW. Go to Tools>Options>Advanced>Firewalls. Port ranges between 49152 - 65535 are usually good to try. For XP firewall make sure you configured it to allow LW full access: Firewall configuration instructions (click on link)