Instructions
Unplug the Wii AC power adapter from both the Wii and the power strip.
Leave the device unplugged for at least two minutes. This resets the console.
Unplug any USB cables.
Check the adapter for two things: First, ensure the adapter is in fact the one that came with your console. It will have "Wii" and the model number "RVL-002" molded into it. Next, check that the power adapter has not been damaged.
Plug the power adapter directly into the wall and into the Wii.
Turn on the Wii. If it comes on and stays on, the reset worked. If it does not, you will need to get your Wii and the power adapter repaired. To begin the repair process, visit the Nintendo support Web page listed in the Resources section.