My ethernet isn't working with airport extreme.

My cord is fine I've tried others and they have the same problem. A few days ago my ethernet kept dropping out and all I had to do was unplug it and plug it back in to fix it. I played with the settings, and tried getting help with it but now my computer isn't even showing an ethernet cord is plugged into my computer. I think the settings on the airport extreme or something may be messed up. I've unplugged it and plugged it back in after a minute to reset it but ethernet still doesn't work.