Has anyone had a problem in which the touchscreen is completely unresponsive in a small section of the screen? I have a half-inch horizontal band in which touches do not register. To verify this, I used a drawing program to draw vertical and diagonal lines, and there is a hard-edged section where no lines were drawn. It appears that the touchscreen is divided into six horizontal sections, and my problem is in the third section down from the top. Seems like a hardware problem which will require a replacement.