Answer to: How to replace the batteryI thought I may have had to replace my battery too. Was going to go down the warranty route. My phone seemed completely non responsive to charging, powering on or anything. Spoke with O2 and was advised to press and hold the Power button and volume down for 10 seconds. This brought up a 'reboot' screen. It mentioned something about the phone being locked. I used the volume up and down to select the Reboot option and then the power button to select the option. Phone rebooted very quickly and was immediately back to working as normal. Hope this helps, if you have the same problem.