Here are a few user friendly and intuitive options for those with dexterity and/or mobility issues in the form of keyboard and computer screen mods. (I'm looking at a certain someone, who sits with her keyboard on her lap and her computer 4 feet away... we'll just call those, "low-tech environmental mods"). When you're ready for an upgrade...
From Microsoft Accessibility (Technology For Everyone):
"Alternative keyboards—featuring larger- or smaller-than-standard keys or keyboards, alternative key configurations, and keyboards for use with one hand.
Electronic pointing devices—used to control the cursor on the screen without use of hands. Devices used include ultrasound, infrared beams, eye movements, nerve signals, or brain waves.
Touch screens—allow direct selection or activation of the computer by touching the screen, making it easier to select an option directly rather than through a mouse movement or keyboard. Touch screens are either built into the computer monitor or can be added onto a computer monitor.
Keyboard filters are typing aids such as word prediction utilities and add-on spelling checkers that reduce the required number of keystrokes. Keyboard filters enable users to quickly access the letters they need and to avoid inadvertently selecting keys they don't want.
Screen enlargers, or screen magnifiers, work like a magnifying glass for the computer by enlarging a portion of the screen which can increase legibility and make it easier to see items on the computer. Some screen enlargers allow a person to zoom in and out on a particular area of the screen.
Screen readers are used to verbalize, or "speak," everything on the screen including text, graphics, control buttons, and menus into a computerized voice that is spoken aloud. In essence, a screen reader transforms a graphic user interface (GUI) into an audio interface. Screen readers are essential for computer users who are blind."
Note the demos and tutorials available from this page:
Types of Assistive Technology