The nintendo ds doesnt recognize all our games?

You can dip a q-tip in alcohol to clean the games, try removing some cotton first so it fits. Do not put anything into the ds system. If that doesn't work you DS might be damaged from the way they force the games in where they bend the pins. Try to find a cleaner for the system. Last--You don't need to buy a DS each time, you can send your system to Nintendo , make a repair order, and for a fee make it work like new. It is still cheaper than a new one. Not sure about used ones, might still be cheaper.