This is a common problem and often caused when a cart is inserted the opposite way round which causes the little raised pins that read the cart to become flattened. You can check this by shining a light into the cart slot and checking the condition of the pins. Unfortunately it's not an easy fix and not for the feint hearted. You'll need to get a triwing screw driver to remove the outer casing of the DS Lite (making sure you keep all of the screws and shoulder L/R buttons safe). The cart slot itself is a sealed unit and this is where the difficulties come in. You'll need to use a small cutting device like a B&D Wizard or a Dremel to cut through the metal housing just above the pins (being careful not to cut too deep) so you can access the flattened pins. Then it's just a simple case of using an awl to raise the pins again. You may be able to perform this fix without the need to disassemble the DS but that would require you to lift the pins by using a shaped tool (perhaps a straightened paperclip with a small hook at the end) and lifting the pins through the cart slot itself (will probably require a lot of patience). Either route you should ensure that the battery is removed before you do anything to the console. Goodluck!
Chan, May 2008
