Instructions
Turn off your Nintendo 64. Make sure a game cartridge is inserted into the console.
Insert the memory card into the controller pack. Push it down gently to make sure it's properly connected.
Press and hold "Start" on your controller. Continue to hold "Start," and then turn the system on.
Release "Start" when the memory-card manager screen is displayed.
Browse through the saved data. Select the game data you want to erase. Choose "Delete." Repeat as necessary if you want to delete multiple files.