The touchscreen may just require a simple calibration which you can perform yourself following the steps below.
The steps are:
1. With the Prodigy unit in OFF mode, press the right button, followed by the left button almost immediately after and hold both buttons down until a white screen comes up.
2. There will be onscreen instructions on calibrating the breathalyser screen. You will need a stylus for this step. The stylus is located on the back of the breathalyser on the top right corner.
3. Tap 3 times each, following the positions of the arrows or crosses that show on the screen.
You can follow instructions on the video below (please press the RIGHT button first, as the video shows otherwise):