All you have to reset it. To do that, turn off the DS, then hold down A+B. Keep holding them down while you turn on the DS. Just before the message that this product is not endorsed by Nintendo, and while still holding down A+B, hold down Start+Select. Keep holding all these down until the Enter Game Card screen comes up. It's tricky to keep all the buttons held down, so you might have to try it a few times before it's really reset. You'll know if it's reset because you'll be able to copy a code over to your DS. That's it.