Your games just aren't connecting properly. This could be because they are not inserted all the way when you turn on the GBA or it could be because you need to clean your games and/or your GBA. Check inside the GBA's game slot to make sure there are not small objects in there. Also check the connectors of your game paks to make sure nothing is stuck in them, either. If they lood clean, gently blow on the connectors to loosen any dirt that may not be visible (you'll want to hold the GBA and game paks so that the openings are facing down when you blow them out, so that gravity will assist you). Alternatively, if you have any canned air handy, use that instead since it is dryer than your breath. Once you have blown out your GBA and game paks, set them somewhere clean where they won't get dust on them and let them sit for about 5 to 10 minutes to clear any excess moisture. After that, they should be good to go. If that doesn't work, you may have a damaged connector inside your GBA, which I don't know how to fix.