slot 1is not holding the cartridge tightly enough to the pins inside the socket, either replace the socket or try this, open up the ds so that the motherboard is exposed the metal cover of slot1 should be at the top of the board as you look at it. In the two bottem corners of the metal casing and the middle with a screw driver or twizzers make small dents dont press to hard, this enables the cartridge to be forced more towards the pins therefore making a better connection, its worked for me many times, so give it a try.
Bill, January 2010
