While we can hope that something like Wolpin's ideas work out for you, in general the phenomenon called ghost touch is a hardware problem that normally requires replacement of the digitizer.
What happens is that the delicate connections between the touch screen's ribbon cable and the glass get damaged, allowing electrical noise on the signal lines. That noise gets picked up by the processor and interpreted as screen touches.
Unfortunately, that ribbon cable requires highly specialized equipment to replace it, so the only real solution is to replace the digitizer.
I did look into this previously for someone else who had exactly the same problem, but unfortunately wasn't able to help with replacement parts or instructions. If you want a little more information you can take a look at the other question here.
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