I got my Sensation yesterday and had a similar issue. My power button got progressively worse as the day went on. It seamed as if the power button was being held by itself and would bring up the power off and the reboot options any time I touched it. Then as the day went on the power button stopped working all together and I can not unlock my screen. Unless I get a call or pull the battery. Pretty disappointed in this as I never even got to take the phone out of the house before it **** the bed on me and now I have to wait till Monday to get a replacement.
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