Originally Posted by pulsar
I got it! You have to unscrew all the screws, and then very carefully push on sturdy inner plastic part, near a corner, and then the screen with the motherboard will start coming off. Just be very careful!
The button I talked about is marked "rst1" - very conveniently. So it must be reset.
I'll post the photo in a few minutes.
Just begging to have a small pin-hole in the back cover!