You should try running kudzu. If you have a PnP ethernet card in your system, it should detect it. Let me know what distribution of Linux you are running, too.
It shouldn't matter that you changed fonts or background colors, or even that you rebooted into Windows. Maybe when you ran netconf it turned on a daemon that didn't previously start up at system boot. I'd try running kudzu, and if it detects your ethernet card, I'd run netconf again.