Symptom: When moving up and down the left side of touchscreen, it
inputs an arch running from the top left to the middle bottom.

I have an old Psion netbook with a four wire touchscreen which I
cannot touch the bottom left. I have done research on the problem and
I guess I am very confused as to why it presents and arch instead of
either working/not working for a particular axis. It seems to
"progressively" fail as I move down the left side.

Does anyone know what is going on electrically? What could cause this?
Any hope of fixing it?

Thanks,
Adam