I've had my analyser for a couple of years - I have hardly used it and now it doesn't work - why?

The reason the FGA has failed may be because the sensors have become exhausted; the electro-chemical sensors have an operational life.

The batteries may also be at a low voltage even if the unit has not been turned on, this is due to the internal memory and clock being powered all the time and most common batteries self discharge over time, lead acid batteries in particular.