At times you may need to perform a reset of your Power Commander III USB. You can perform the reset procedure by connecting it to the software and powering it up. Once you have communication established go to the "Tools" menu and select "Environmental Options". Once you have selected that option a window will appear that has a black rectangular button at the bottom that reads "Reset Power Commander". If the button is not visible then you would have to hit the "Control" and "R" keys at the same time on the computer keyboard to display it. If you are using a custom map or one that has been altered, make sure you save a copy of your map first, as the reset procedure will zero out the map and reset the power commander to the factory default settings.