Unexplained Burnout

Hi, I am wondering if anyone can help me regarding an annoying issue. Everyday in the office one of the laptops will not connect to the network. But when I change the wires from the port patch to the hub, the laptop will connect back to the network.Now I can’t really diagnose the problem because the person who uses the laptop wants it connected straight back to the network and he is my boss, so I can’t complain. But what can the issue be? Please help someone.