The router is Zyzel Prestige 600 series. I do not want to reboot as this PC, I am talking to you on, routes through it and I do not want to risk loosing any more connections. I can tell you that patching this PC on to any of the router ports lights them up. Only the port with the Knoppixed PC does not light whichever port it is plugged to. So I would think it is not due to a router problem as the "no light" firmly stays with the Knoppixed PC except when running Knoppix live CD. Any further thoughts please?