[OP2] How to get Network to work again

[Sailoog]

OK

If you take the USB wifi device it should work, try it.

But we need to know what produces this error. Plug in the USB wifi device again and type:
ls /sys/class/net
then try this for every value you get from the previous command:
ls -l /sys/class/net/eth0/
ls -l /sys/class/net/wlan0/
...
and send me the output.