How to fix my networking controller

First of all, are both the lights on the ethernet port lit up? If they are then it's most likely a cable or driver problem. Try the ethernet cable in another computer and if it works, try reinstalling drivers. To do so, hold down the windows key + R and type in "devmgmt.msc" in the box that appears. Expand the "Network Adapters" section and right click on your "Ethernet Controller" driver and hit uninstall. Don't check the delete checkbox that may appear on the first prompt, but just keep hitting ok until the dialog boxes stop. Then restart your computer and see if the ethernet is working.