I've been having the same problem. Factory reset didn't help either; I have to reboot my phone about 5 times per day because of freezing issues. Has anyone explored the possibility of this being a problem related to the keyboard. The one thing I have in common between all freezes is that it always happens when the keyboard slides out. It may not be much, and barely noticeable, but if it slides out in my pocket a little bit I usually have to reboot my phone.