I've had my Shift since early September, and it's been mostly pyoblem-free since then. Recently, it's begun rebooting itself randomly. Sometimes I'll back out of an app, or press an app icon, and next thing I know, the screen goes black as the phone reboots itself. Any ideas what could be happening? I haven't taken it to the Sprint store yet (unforgettable aggravation), and hope I don't have to.