If you see network cable is unplugged error after having a network connection between your computer’s network card and router/switch, then you can try following tips to solve the issue:
- Check and confirm that you have used the correct network cables (straight or crossover) to make the connection.

- If the network cable is correct, then you can try to use other network cable and test it. Sometimes the problem can be due to faulty network cable.

- Connect the network cable to other ports of the router/switch. Sometimes the problem can be due to faulty network port on the network devices.

- Disconnect and reconnect the network cables on both connecting devices to ensure there is no loose connection.

- Ensure the network card driver is installed properly. If not, reinstall it again. Also you can go to manufacturer website to download the latest driver for your network card and install it.

- If you have extra network card, then replace the existing one to test whether it’s network card problem.

- Also you can try to set auto or specific link speed and duplex mode on network card and see whether it works:

10Mbps and Full duplex
100Mbps and Full duplex
1000Mbps and Full duplex
10Mbps and Half duplex
100Mbps and Half duplex
1000Mbps and Half duplex
Auto Detect