Accessibility
The three main things that make computers difficult to use are: the monitor, the keyboard, and the mouse.
For older users and those whose schooling did not include computers, the mouse is the main hassle because it is totally different from anything else they've learned to use. Single click? Double click? Left click? Right click? Click and drag? Drag and drop? None of this is at all easy to master.
For those who did not take classes that included keyboarding (or "typing" as it used to be called until the keyboard acquired about 45 additional keys), creating an email message with much content can be the work of hours. As the eyes change their focal lengths, the monitor itself, being vertically inclined, becomes the enemy of ease, creating neck pain and headache as one constantly strains to alternate between focus on the keyboard and the screen, no thanks to the nauseating intervention of bifocal lenses.
We are not yet in the era of ubiquitous voice response, as per Star Trek, where one can say merely, "Computer, where is my other brown sock," and instantly receive coordinates for the dryer. Nevertheless, as time moves on, computers become increasingly accommodating for those who need assistance in using them. The following sites may be helpful to many who have needs that prevent their easy use of personal computers. These are but pointers to the whole field of accessibility.
Microsoft's Accessibility Site offers tutorials for such things as adjusting the accessibility features of your computer. Some of these offers tutorials for such things as adjusting the accessibility features of your computer. Some of these features are not set up by default, but can be added by following the instructions on this site.
Google's Directory provides links to a wealth of informative websites that deal with, or sell appliances for, computer access.