Hi

I work somewhere for two weeks at a time where your not allowed to use a mobile ( and not allowed to half it on your person so you can charge it either). With other phones i just charged the battery before the two weeks and then turned the phone fully off and there used to be at least half a battery charge left after two weeks.. Cant seem to do this with the 8100, its always flat. Think I am not "fully" turning it off? Cant seem to find the exact method of turning it totally off?

The only way to really shut it off is to remove the battery.

How are you attempting to turn it off? If it's with the button on the top of the device, that only puts it in stand-by. It will continue to consume battery power in this mode, though more slowly than when fully powered up. From you home screen, select the 'power off' icon. This will do the trick. You can press the red end key to power on again.