Unable to calibrate Nuvi 465 touch screen.

Hello,
does anyone know a different method how to calibrate the screen on Garmin Nuvi 465T
I already tried:
a) pushing and keep it pushed the ON/OFF slider to the ON position
b) Keep the finger on the upper left corner,while device is booting
c) Slide fast ON/OFF ,return it to lock position and keep the finger on the middle of the screen.
None of the methods worked.
I even tried to downgrade the firmware to the lower 330 but did not help either.
Any ideas or suggestions?
Thanks in advance.