Incompatible Disc
The Nintendo Wii is compatible only with special Wii discs or the mini-discs designed for the Nintendo GameCube. Unlike the Xbox 360 or PlayStation 3 consoles, the Wii does not play regular DVDs or CDs. Make sure your disc is designed to work with the Wii.
Disc Loaded Incorrectly
You must load the disc properly and position the Nintendo Wii correctly for it to read discs. If the Wii is in the upright position, make sure the disc label is to the right and the shiny reflective side on the left when you insert the disc. If the Wii is lying flat, the label side should be up and the reflective side on the bottom. If the Wii is in this position, also make sure that it is not upside down, as the machine cannot read discs in this position. The three buttons and the SD card slot should all be below the game disc slot.
Damaged Disc
The Wii can have problems reading a disc that is either dirty or scratched. Hold the disc up to the light with the reflective side up and inspect the surface to see whether there is any damage to the disc. Dust buildup, fingerprints and even minor scratches can be remedied with a gentle cleaning. Wet a soft cotton cloth with plain water and wipe the reflective side of the disc from the inside to the outer rim in straight strokes. Do not use circular motions.
Repeat the wipe-down with the dry part of the cloth, then let the disc dry for several minutes before reinserting it into the Wii. If this does not fix the problem and the disc appears to have scratches or imperfections, it may be beyond repair.