How to check whether its working or not working?

If your PC LAN Card is active just connect the switch with Straight cable - & --you will see one yellow box in ritht side corner down to monitor screen...where the time appears.....also you can check in the Network Connections Folder. Or Right Click My Network Places> Properties> You will see local area Network....> Connected...then it is working if disconnected it's not working....Good Luck

When the computers are powered up and connected to the D-Link hub,
the computers that are connected to the hub will light up the various LEDs on the hub to indicate which port on the hub is active. Also that computer's network card Link LED light should be on to indicate it is connected to the hub.
If the hub's LED is off and the corresponding computer's network card Link LED is off then the network cable is faulty, or the network card is faulty (or the network card driver needs installing) or the port on the hub and/or hub is faulty.
To determine which item is faulty, swap network cables around, swap computers to different ports on the hub etc.