Local area connection shows unplugged. We put a new router in at my office, we all had to change

Question

We put a new router in at my office, we all had to change our IP address and other connections, my computer worked fine for two day, turned it off last night and this morning I do not have a connection. The only thing different was I had to unplug the ethernet cord and plugged it back in. I have checked the connections everywhere, shut down and restarted, tried a new connection cable, checked the new settings and they are right. Any suggestions would be appreciated. I don't know if the site took my product info. HP,desktop, Pavillion 6745c series Thanks Carol