Things You'll Need
Instructions
Turn off your N64, and insert the GameShark cartridge into the cartridge slot. The label on the GameShark should face toward the front of the console.
Insert the different N64 cartridge into the slot on the top of the GameShark.
Turn on the N64, and wait for the GameShark screen to load. The LED indicator on the front of the GameShark cartridge will count down from five, and the menu will appear once the counter reaches zero.
Open "Key Codes" from the main menu, and select "Diddy Kong Racing." The system will display a warning message asking if you have the game available. Select "Yes."
Turn off the N64, and remove the game cartridge from the top of the GameShark cartridge. Insert "Diddy Kong Racing" into the cartridge slot on top of the GameShark, and turn on the console. You can now use codes on your game.