Z82 is not responding

Can you get in the diagnostics menu settings and perform the test and mag. calibration?

Press "up" key down and repeatedly press the "down/power" to get in this setting.

cycle to the settings with the "measure red stripe" button.

Have the z82 shut down again and try rebooting.

If not working go back to the diagnostic menu and keep it in the screen test setting to let the battery drain.

Then when battery is drained recharge and try to start again.