I rebooted using a bootlable USB stick and the network wasn't there. I rebooted again into the same one and the network was there. I've seen several USB ethernet adapters for less than $15 on Amazon. I guess I'll get one of those.For the ethernet adapter, I would check and see if a bootable thumb drive has the same behavior. This may be a hardware-related issue and ruling that out might be a good first step.
The system presents me with updates almost every day, but I'm guessing I can rule them out since the problem persists when I booted from a PartedMagic iso I've had for several months. Thanks.Were there any recent kernel or system updates that would have affected how your drives are identified? Bios setting?