Why would a Wii controller not work when I hook up the system for the first time?

I had no problem with the system setup; however, when I inserted a game into the system, it doesn't recognize the controller.Why would a Wii controller not work when I hook up the system for the first time?
Did you hook up the controller before or after you plugged the system into the power? Try unplugging it and then plugging it back in.Why would a Wii controller not work when I hook up the system for the first time?
when my youngest son set up the wii the first time, he had never seen one set up. He plugged all the pieces into the television, and console right. However, the ';controller bar'; that reads the controller he sat up incorrectly. He had the bar itself lying down flat on its face on the telly. So the Wii couldn't see a signal.
You need to Sync the Wii-mote with the system. To do this, Open the front flap of the Wii and youw ill see a small red button labeled 'Sync'.





Keep that open and take the battery cover off of the Wii-mote. You will see the same button.





Press the one on the Wii, then press the one on the Wii-mote. They shoudl be synced. you will need to do this every time you bring a new Wii-mote to play with.