It is difficult to diagnose a touchscreen not working without more information, but here is a list of items to consider.

1. Restart your device, including unplugging and plugging back in.
2. Try adjusting the screen brightness and sensitivity settings.
3. If applicable, make sure you are using a stylus designed for you device.
4. Try cleaning the screen with a damp cloth.
5. Check the device’s connections for damage.
6. Try a forced reboot, if available on your device.
7. Contact a customer service representative for your device.