Start 25 touch screen Calibration problem

Shar0n Registered Users Posts: 1
New Traveler
I've had my Start 25 SAT NAV for about 3 years now, but only use it occasionally. The last few times I've tried to put a new destination, it has taken me ages as when I touch a letter on the key pad, a letter to the right of it shows on screen (eg, if I touch D, F or G will appear). This is getting worse & it is now almost impossible to enter a new destination. Does anybody know if it can be recalibrated? I have tried resetting the SAT NAV