8BitLlama

The only thing I can think of is because its not showing up as a sound device and just a "other device" is that the driver you are installing is either the wrong driver or the driver for another version of windows.
 
And or the presence of the usb sound card is messing with the onboard sound

Try booting into safe mode and run DDU "Display Driver Uninstaller" and chose audio realtek and clean and restart and then install the latest realtek drivers.  Let us know what happens.

There isn't harm in trying. I'm guessing that the 2 Ethernet ports are there for an extra device to be hooked up. 

yes it works,i got it working last year from a win 10 system to a win 7 one

You will need to set the 2nd port in bridge mode and follow this guide.
 
http://www.windowscentral.com/how-set-and-manage-network-bridge-connection-windows-10

i dont really remember,it was pretty easy and i got it working just by trying stuff

Alright thanks everyone who posted; I read about everything you all posted and went to my adapter settings and bridged both connections together. for a few seconds I had no internet but then both pc's connected and are both on wired.