You are teaching your grandparents to use the computer what should they know?

Well, I'm working on teaching my technologically challenged dad the basics of computing, and so far I've found that the most important thing to teach them (other than stuff like the keyboard and mouse) is how the hierarchy of folders works. Before I showed him that, he used the computer like a typewriter, simply re-typing everything whenever he needed it again. Also, tell them not to be afraid to poke around. Even if something goes wrong, the things they learned by looking around their computer will far outbalance the negatives. There you go, and good luck!