Deleting Game Save Data
All Wii games and Wii Channels that create a save file (such as for game progress, high scores, channel settings) that can be deleted or copied.
To delete save game data
1. Access the Wii Data Management screen (look here
2. Select the "Save Data" icon to display all save files.
3. Select the file you want to delete.
4. Select "Erase" to delete the file.
Warning: If a game save file is deleted, there is no way to get it back. Be sure you want to delete it, or even copy it to an SD Card if necessary.