dudley61,
Shutdown your computer.
Plug the ethernet cable from your computer into a numbered port in your wireless router or into your modem.
Start the computer. It should connect immediately. To make sure, try turning off the wireless adapter, Fn and F2 or F2 or some models have a switch on the side.
If you have a model that has a light, the ethernet adapter may have a light to show it's working.
Rick