My sons Droid LG Ally has been turning off while he is using it. The battery has at least 50% chrage on it and it will go to a black screen with the words DROID then shut off. You can turn it back on just fine but it's only a matter of time before it happens again. He also told me it will happen when he is trying to text his friends. Is there a setting he messed with? or maybe reasigned a button to turn off his phone? Thanks.