Unplug the USB cable (either end).
Hold down the Arduino reset button.
Plug in the USB cable.
Click on the sketch Upload button.
When you see the "Binary sketch size:" message, release the reset button.
Unplug the USB cable (either end).
Hold down the Arduino reset button.
Plug in the USB cable.
Click on the sketch Upload button.
When you see the "Binary sketch size:" message, release the reset button.