I replaced the connector on my ethernet cable after the locking tab broke off. I tested the cable with a PS4 since the PC was shut down. It worked properly so I tried it on my PC. It didn't detect the cable being plugged in so I tried a different one. It worked fine with the second cable. I've tried reinstalling the network adapter drivers, changing the speed and flux settings and performing a system restore. I'm not sure what to try next.