Complete all steps, in the order that they appear, in the Quick Setup Guide provided with the Wii console.
Make sure all components of your setup are plugged into appropriate power outlets and inputs; and that the power switch on the power outlet is set to the ON position.
Ensure the television display is set to the correct AV or INPUT channel, according to which input the Wii is connected to.
If using the Wii Stereo AV cable ensure the yellow video plug is not plugged into a blue, red or green component input on the television display. This is only for component cables.
If using the Wii Component Cables, they need to be plugged into the appropriate Component Inputs of the television and not AV inputs.
Occasionally the refresh rate set on the Wii console may not be compatible with your display. To reset the refresh rate:
Power ON the Wii console.
Press and hold the ‘DOWN’ key on the Wii Remote directional pad.
While still holding the ‘DOWN’ key press the ‘RESET’ button on the Wii console.