Hi,
I got the same problem as most of you, touch screen died
suddenly (RU 950). As Pronto is crucial in my HT I even
bought a new one (RU950). After that I could start to
analyse the problem in the old one with a good concience!
And alas, I found the fix, which will cure both dead screen
but also the failing calibration (actually the same basic
cause). BTW If the Pronto Team doesnt really know the
problem - I am disappointed.

The nice thing about the fix is that it does not cost
anything, but you have to be able to open the whole plastic
cover system properly.

Disclaimer: I do not take any responsibility of this fix
- you try it at your own risk!

First you have to open the plastic cover system (there
are 5 torx screws holding the upper part, 4 visible and
one inside). After that you may be able to take off the
green rim round the touch screen. When that is done, you
will see a flexible connector (carbon to copper) at the
upper right corner of the touch screen. And that is the
cause of the problem! There are four connection points
(o o o o) which should make contact with the flexible
copper strips beneath them - but for some reason they
lose their connectivity after some time (oxidation?).
So the simple fix is to rub the connection points with
a sharp object (model knife, opposite end of a needle).
Be careful not to puncture the plastic (or break the glass!)
but still use enough power to ensure a good contact...

If only one connection point is faulty you will get calibration
error, if more, the touch screen does not work at all.

If Daniel allows, I could send some pictures to make it
more clear to u all.

Hope this helps, it surely helped me - :-)

regards PeraV