Instructions
Observe the connection that has been made between your Nintendo Wii and your TV set. This audio/video cable connection may have been made in one of two ways. The first way is via a standard composite cable, which is a black cable that features a set of yellow, white and red prongs at each of its ends. There are matching yellow, white and red composite ports on the rear of the Wii and your TV. Check the prong-to-port connections here and ensure that yellow prongs are connected to yellow ports, red prongs to red ports and white prongs to white ports.
Check the connection between your Wii and your TV if you used a component audio/video cable instead of a composite cable. Component cables differ from composite in color. These cables feature two sets of prongs consisting of one blue, one red and one green prong. Ensure these are color-matched with the blue, red and green ports on the back of the Wii and the back of the TV.
Check the Wii's power indicator light. If it is orange or green, press and hold the power button for up to ten seconds for the system to shut down.
Unplug the Wii's AC adapter from the power outlet if you can't shut off the Wii with the power button.
Power the Wii back on and allow it to boot up. The console should be de-bricked.