Wii Remote Problems
The Wii Remote may not be recognized by the console upon first starting a game or turning on the machine. If this happens, there are a number of things to check. First, turn the Wii on and open the flap at the front of the console. There is a red button there called the Sync button. Press the small button below the batteries on the Wiimote, and wait for the blue lights in front to blink. When this happens, press and release the Sync button on the console. Repeat this process for each Wii remote to sync them to the machine.
No Power
If the Wii Console will not come on, check to ensure that the Wii and the AC adaptor are compatible. Note that unlicensed products are not always fully compatible with the Wii and may cause the system to work improperly. This also goes for ancillaries such as memory cards, controllers, and other devices that may claim to work with the Wii. Finally, check all power supplies for damage and make sure the Wii has proper room to ventilate.
Disc Errors
Disc errors can occur is the game is inserted incorrectly. Make sure you have inserted the disk correctly by using the following rules of thumb: if the Wii is oriented vertically, the disc's label should be facing the right hand side as it is placed in the machine; if the Wii is lying flat, the disc label should be facing up. If only one game is giving you errors, try cleaning the game.
Online Problems
If you're experiencing online problems such as errors while trying to connect or slow download times, try changing the channel on the router. Changing the router's channel to number 1 or number 11 can sometimes resolve this issue, as these channels do not overlap, and will alleviate interference. Additionally, if possible the router should be placed in a central location in the house, away from walls.
Sound or Video Problems
If there is nothing wrong with the hookup, but you are experiencing sound or video issues with your Wii, check to make sure that the game itself is not the problem. Do this by going through the Wii channel and the menu. If the problem is gone, and other games work correctly, the game may be defective. If these problems continue on those channels, the problem may be with the console itself, and you should notify Nintendo.