Desktop keep searching for 'Identifying' network but unable to connect through Router

I am using internet broadband provided by local cable network, they have installed an optical fiber lan to connect. It works fine with the desktops.

I have installed a Router with wifi for our network to share the same bandwidth. Now all the laptops connects smoothly by wifi. If I connect any laptop by wire, it also connects. But none of the Desktops are unable to connect through wire. It just keep trying to identify the network.

I think it's an issue of the desktop o/s (Win 7 Professional). Please suggest any solution.