Hello everybody, I have had the Nexus S for a while now, and about 5 months ago started having the power button issue where it won't lock or unlock the phone. Being that the issue was irregular, I figured it was a hardware issue. After finally getting fed up enough I decided to open the phone and see what I could find. What is happening, is there is a ribbon connector directly across from the power button on the back of the phone that gets loose or disconnects itself, and this is why the power button is not working. All you have to do to fix this is open the phone up and reconnect the cable. You can do this by removing the battery and six screws from the back of the phone. You cthen have to pop the sides off of the black piece that runs around the screen. This part is tricky so be careful not to break it. You can then pull the back internal back off the phone and reveal the electronics of the phone. Simply reconnect the ribbon connectly right next to the power button and your power button will work. This is what worked for me - be careful while doing this as you will be around all the electronics of the phone. Don't blame me if you screw it up while attempting this.