If your second display is recognized by the system but is showing a black screen, you might have it set to only show a picture on the laptop screen. In Windows, open Settings > System > Display ...
My laptop display is used for writing and editing and ... so you’ll have to jump into Windows Sound Settings to switch it back. The manufacturer’s suggested retail price of the Cevaton S6 ...
If the glass on your laptop touchscreen is cracked or ... Open Control Panel > Hardware & Sound > Tablet PC Settings > Calibrate the screen for pen or touch input. Press the Rest button.