Dead spot in touch screen 2007 Tahoe LTZ

[MVISSER]

I just bought a Tahoe, with 73K miles on it. The nav and radio work great, except there is a dead zone in the middle/top area of the screen. It won't respond to my touch unless I press really hard. I am afraid I will break the screen. The lower and upper edges of the screen work well. Does anyone know if this can be repaired or does it mean replacing the entire unit?