I am pretty much in the same boat. I ditched Windows for Ubuntu Studio, just got it set up and my wired connection doesn't work and I even have the same problem with my external hard drive.
The activity lights on the ethernet input blink and are active, but no internet connection or network access. I don't see any networks on the network list. I even tried a wireless card that came with the mother board, but no networks popped up, and when I look up solutions the network manager that people describe looks nothing like what I see. I also don't have a device manager. Am I doing something wrong? Specialy seeing that the person above me also has the same problems (at least mostly) is there anything we can do. Or if you, the person above me, solved the problem (seeing as this is an older post) and you notice this, can you tell me what you did? Thanks to whoever helps.