A factory reset re-calibrates a number of low level controllers, like RF controllers, CD controllers (where applicable) and resets the operating system - often resolving most anomalies found.
Please note that performing a factory rest will remove any presets, timer and alarm settings you may have stored in your product. You will need to re-enter these when the reset is complete.
Start by making sure your aerial system is extended vertically. With the radio turned on, press the Menu button. Scroll using the < > buttons to 'SETTINGS' and press the Select button. Scroll < > to 'FACTORY RESET' and press the Select button twice.