Do you mean you can use the A button (left most button) to select icons but you can't activate them with the B button (middle button)? If that is the case, can you get it to work at all by pressing down harder? If it doesn't do anything to the Tamagotchi it is probably faulty, and your best option would be to return it (you could possibly open it up and check to see if there is anything between the buttons, but that might violate your warranty).