For days now, every time I try to unlock my phone (usually to read a text message I just received), it powers off the phone the second I touch the screen. This happens without fail, at the same point, every time. Once the phone shuts off, I turn it back on, wait for it to boot and then I can use the phone. If I put it back into standby mode, it will shut off again once I try to unlock it. Anyone else ever have this problem?