Final answer:
a) Check the network cable connection at the workstation. When troubleshooting network issues, start by checking the network cable connection at the workstation.
Step-by-step explanation:
When troubleshooting network issues, it's important to follow a systematic approach. In this scenario, since the user's coworkers claim no issues and there are no LED lights on the user's network interface card, the next step would be to check the network cable connection at the workstation.
Verify that the network cable is securely plugged into both the network interface card on the workstation and the network port on the wall.
If the cable is properly connected and the issue persists, the next step would be to verify the switch configuration. Check if the port on the switch for the user's workstation is configured correctly and is not disabled or blocked.
If the switch configuration is correct, the final step would be to inspect the network port on the switch. Make sure the port is not damaged or faulty. You can try connecting another device to the same port to see if it works.