A game cartridge with a game program configured to cause a computer to implement a jukebox or music playing method. The method includes displaying a listing of game modules of the game program on a display screen including a jukebox module. A selection to activate or run the music player module is received. The music player module plays music by outputting to the audio output port an audio signal based on processing of the digital music files stored in the storage medium. The method includes receiving a sleep mode initiation signal such as may be transmitted in response a magnetic sensor sensing closing of a housing or lid. The method includes responding to the initiation signal by placing the game modules except for the music player module into a sleep state, whereby the music player module continues to play music after other modules are paused.