There are several reset methods for the WDT60 mobile device.
A Warm Boot terminates an unresponsive application and clears the working RAM, but preserves the file system. Registry is restored from persistent memory if available or returned to factory default.
To perform a Warm Boot (useful if a program is stuck):
Press and hold the orange button, the blue button, and the red phone button (bottom left, bottom right, and top right) until the screen goes black, then boots after a few moments.
Turn off the device with the power key (upper left), remove the battery, press the button in battery compartment (right side middle) for about 1 second, replace battery, turn on the device. It should boot with a few messages, then it should say Cold Boot, and boots after a few moments.
A Clean Boot restores the WDT60 to a clean configuration: both the Registry and the file system return to a clean status that conforms to factory default. This erases all user-installed programs and files.
To perform a Clean Boot:
Set the device down on a table so you can use both hands. Press and hold the orange, blue, and red phone buttons (the Warm Boot procedure). After the screen goes black, before the Wasp splash screen appears, press and hold the 0 and the red phone keys. A dialog will appear asking for confirmation (it may be a bit hard to read). Release the 0 and Red Phone. On the CleanBoot Request Detected confirmation screen, the orange message reads "Press Enter to Confirm; Press ESC to Cancel". Press the ENT key to confirm (lower right). If you wish to cancel the Clean Boot, press the red phone key.
The movie file linked below demonstrates the Warm Boot keypresses, and continues with the Clean Boot's 0+Red Phone to show the confirmation screen (the movie ends here). At this point, press ENT on the keypad to confirm the Clean Boot, or press Red Phone button to cancel.