Help Asus ZenFone 2 suddenly turns off.

[Stijn De Mulder]

I was chatting and watching some notifications on Google + and suddenly my phone turns black and it doesn't react to anything. When I put it in the charcher, or connect to pc, the ony thing it does is vibrate after 10-20 seconds or so and my pc can't even find the device. I can't turn it on either.
I can't "restart" it by removing the battery since the ZenFone 2 has no removable battery ...

please ... please help !!!