CAMBRIDGE, Mass. -- The $100 laptop computers that Massachusetts Institute of Technology researchers want to get into the hands of the world's children would be durable, flexible and self-reliant. The machines' AC adapter would double as a carrying strap, and a hand crank would power them when there's no electricity. They'd be foldable into more positions than traditional notebook PCs, and carried like slim lunchboxes. For example, to keep the $100 laptops from being widely stolen or sold off in poor countries, he expects to make them so pervasive in schools and so distinctive in design that it would be...