I have a brand new (p.o.s.) Sony Ericsson, and starting last night some time, a light blue box with a capital H appeared on the top, left hand corner of my screen. Since then, I can't send ANY text messages, not even to myself (but I can receive them sometimes). AT&T Tech Support doesn't even know what the blue box is. I'm going crazy and want that stupid box off my phone. Help! Thanks.