G5 network pane will not open and unable to connect to internet

Hello

I have a Power Mac G5 with 10.5.8. Actually just getting ready to retire it but it will not connect to internet.

When I open a browser the message says I am not connected to the internet.

When I then try to open preferences and click on the Network icon the pane open but then when I try to to click on the "Built - In ethernet" the spinning beachball shows up and hangs.

I have test the ethernet cable from the wall by hooking up to a MacBook.

I cannot see that this is the ethernet physical port as otherwise the network pane should open ok?

I did a repair permissions and that did nothing

Also moved some preferences to the trash and reboot and no luck.

Any suggestions would be appreciated.

Mac