Most PC's have one or to LEDs to indicate connection and/or connection speed close to the network connector, check whether they light up or not.

>This is a laptop. But the problem I have is not with wireless but with the hard-wired networking.
>
>>If this is a laptop, it most likely has a switch to disable all wireless communication so that you can use it in a plane.
>>
>>>Hi,
>>>
>>>I was using my PC earlier today on a wireless network (at home) without any problems. I came in the office and plug in my cat5 cable but the network icon says unplugged. I tested the network cable on another computer in the office (on which I am typing now) and it works. But when I plug it into my " other" pc it does not work. In the Control Panel -> Networking, the network card does not seem to have any problems. That is, it says, "working properly"
>>>
>>>What else can I do to troubleshoot this issue? Maybe related or maybe unrelated, also this morning the cordless keyboard does not communicate with the computer.
>>>
>>>TIA for any suggestions.