Just a heads up, if you were getting DDoS'd, it doesn't cause your screen to freeze. Getting DDoS'd is basically like losing your internet connection, you can still move around, but everyone still appears to be standing still, then you will usually "time out". If you were freezing/crashing like you stated, then that indicates a more client-sided issue, either an error in the client you're using, or java, or perhaps even in your PC.