The problem isn't that these people can't use computers. It's that they can't THINK. They do not understand what critical thinking is, or how it works. They do not know how to approach problems or explore solutions. They don't know how to do it with their computer... or their car, or their vacuuming robot, or their television, or their oven or their relationships or any thing in their life. They don't understand why the world is the way it is, they don't know how to figure it out, and they generally think that trying is a suckers game.
You mention that there are always 1 or 2 kids a year who have already picked up programming or know how to build a computer... I think I would live for them. I was one of those kids, and I would be so excited for them that I would bury them in whatever help they needed.
For the other kids, I'd put aside the computers for a bit. I'd teach them critical thinking, because it's really the only skill they need to learn (see the documentary "High School" by Wiseman for an excellent example of how reformulating every single class as being centered around critical thinking led a poor latino high schools students to accomplish the highest percentage of students to attain college degrees in the nation... while preserving their youthful exuberance for learning).