Mine is doing this now too. I haven't used the USB cable in a week or so and I usually only use it to charge -- most of my file transfers are ftp over wifi. But today when I plugged in the stock USB cable I rebooted. I tried plugging it into the phone first, then computer.. and computer first then phone.. rebooted over and over until I unplugged it. I'd sure like to know why and what to do about it.