What I sometimes forget is that many of them use computers but are barely comfortable doing so, and no one has really taken the time to make sure that they know how to do the things to make themselves feel at home with their computer.
Today a client's daughter suggested that she might not have responded to an email because I didn't make the type size in the email big enough.
(Since when is it the sender's job to guess what the right reading size is for the recipient?)
I asked if daughter had taught Mom how to use CTRL+ to raise the size of any email that has print too small to read? (CTRL+ makes the email body content bigger, CTRL- reduces it)
(For you Mac users, it's Command+ to make text bigger, Command- to make it smaller.)
Try it, you'll like it!
Works almost everywhere -- should usually be the first thing you try if you are having problems reading text or making out an image on a screen.