Press and hold the Top Right (Power/Tool) button for 25–30 seconds . Do not let go when you see the CASIO logo appear.
Once in Recovery Mode, the touchscreen is disabled. Use the physical buttons: How to Hard Reset CASIO Pro Trek WSD-F20
If your touchscreen responds to touch inputs, the standard Settings menu provides the safest way to execute a factory reset. Press and hold the Top Right (Power/Tool) button