Reinitializing the unit resets it back to the factory defaults.
To do so press both Cursor buttons and while doing so power up the unit. This takes us into a Diagnostics mode. Now turn the data knob until you see Initialize User data (Initialize NV RAM on the Audity). Hit the Enter button twice to perform the reinitialization.
To reboot the unit simply turn the data knob until you see Reboot.
Press Enter twice to reboot the unit. Powering off and then back on again will work too!