Touchscreen does not work

The keys on the touchscreen do not work

Remedy:

1.  Clean the surface with a moist cloth. Check also for scratches or damages.
    
2.  Check if the frame presses on the touchscreen. The active surface is bigger than the screen.
        If necessary bring some clearance  between the frame and the touch.
    
3. If you tip simultaneously on two spots, the touchscreen can block for a short period.
       Wait for a couple of seconds.