Instructions
Make sure all cords and attachments are connected securely and properly to the Wii and to the Wii's power source (wall outlet, power strip, etc.) if the console isn't turning on or appearing on the screen once powered up. Check (and replace if necessary) the batteries on the guitar remote if the system powers up but won't play.
Press and hold the "On" button on the drum kit and mic controllers. Hold down the wireless plug at the same time until the unit flashes a red light. Release both at the same time, and only one of the controller lights should be lit. This helps calibrate the drum and mic controllers.
Remove the back of the guitar controller and manually loosen the infrared sensor at the bottom. Shift the darkened sensor plate to the left or right, which helps calibrate the sensor so it will align with the sensor on the Wii console. Do this if the guitar is unresponsive, despite having new batteries.
Wrap a rubber band or elastic hair tie and around the whammy bar flip switch on the face of the guitar remote if it feels loose or won't perform properly. Conversely, if the colored buttons on the remote's neck seem loose or unresponsive, a purchase of a new guitar controller may in be order if the unit isn't still under manufacturer's warranty.