"JohnK" <Duh@Duh.com> wrote in news:gJeAk.42092$Mh5.4407@bgtnsc04-
news.ops.worldnet.att.net:

Look very closely at the surface of the screen by reflecting light off it
with the unit off.  Are there any tiny dimples in the screen, anywhere?

Those dimples are making "contact" without pressing them, confusing the
scanning electronics into thinking you are pressing where the dimple
is....overriding other points along or near the same vertical and
horizontal lines across the screen.

The cure is probably to replace the touchscreen if there are dimples you
cannot recover.

Dimples stick INTO the screen.  Gook and minor point scratches stick out
and don't do to the electronics what dimples do.

The screen in any real touchscreen device must be protected from being
pressed hard by anything, especially pointy things.