Wii remote

you need to smack the wii controller on your hand like you were hitting a fly. trust me, this happened to me before, when my wii just came out of the box.

another solution would be to test the sensor bar and here is how to do it.
First turn on the system and get it to the main screen. Next get a digital camera or a camcorder and aim the camera at the sensor bar. there are a series of lights on either side of the sensor bar five on each side.if all the lights are lit then it is a problem with the remote itself, if one side of the lights are off or none are on then the sensor bar needs to be replaced. Sometimes the sensor bar just goes bad and needs to be replaced. If it is still under warranty you can call the customer service number that is located in the back of the instruction manual and they will send you a new one free of charge. Make sure before you call that you have registered your console with Nintendo, it makes the process much much easier