Share your experience!
my z2 dropped flat this morning, with its back on the floor. 
when i pushed the power button on, the screen is a complete black out yet its back light are on (indicating it is turned on).
I have charged my phone and charging light is ok. Yet if i push the power button on, only the back light are turning on. 
Is this a hardware problem already? 
This is the 3rd time I dropped it. 
I suggest that you try to repair the phone software using PC Companion..
Before repairing your device you may want to backup your information first. Check out this topic for more information on how to.
How to backup?
If the issue should still remain I think that this needs to be examined and fixed at a repair center. For more information about how to submit your phone for repair and where, contact your local support team.
Thank you Samuel for the tip. Appreciate it!
Guess I'll try to reset my phone with PC Companion first.
If not fixed, then ... 