Some individuals with disabilities require assistive technology (AT) in order to access computers. Hundreds of Windows AT third-party products are available, making it possible for almost anyone to use Windows® applications, regardless of their disabilities. The Microsoft® Windows® operating systems also provides a core set of basic accessibility features and AT applications, which can be deployed on all computers in a computer lab or classroom without additional cost. These applications provide students with basic accessibility features from any workstation, maximizing the inclusiveness of the learning environment.
It should be noted that the AT applications that are bundled with Windows provide only a minimum level of accessibility, not the full set of features that many users require for equal access to the operating system, educational programs, and other software applications. Therefore, many educational entities deploy the standard set of Windows AT on all workstations by default, but additionally 1) provide a small number of dedicated workstations that are equipped with commonly requested third party AT, and 2) are prepared to purchase and install additional AT as needed by specific students.
It should also be noted that the availability of AT does not itself guarantee accessibility. Software applications must be designed in a way that is compatible with AT and other accessibility features of the operating system. For information about purchasing software products that are accessible, see the AccessIT Knowledge Base article How can I tell whether a software application is accessible? 
The following is a list of basic accessibility features that are included with Windows XP. Previous versions of Windows also included several of these same features.
Display and Readability:
These features are designed to increase the visibility of items on the screen.
- Font style, color, and size of items on the desktop—using the Display options, choose font color, size and style combinations.
- Icon size—make icons larger for visibility, or smaller for increased screen space.
- Screen resolution—change pixel count to enlarge objects on screen.
- High contrast schemes—select color combinations that are easier to see.
- Cursor width and blink rate—make the cursor easier to locate, or eliminate the distraction of its blinking.
- Microsoft Magnifier—enlarge portion of screen for better visibility.
Sounds and Speech:
These features are designed to make computer sounds easier to hear or distinguish - or, visual alternatives to sound. Speech-to-text options are also available.
- Sound Volume—turn computer sound up or down.
- Sound Schemes—associate computer sounds with particular system events.
- ShowSounds—display captions for speech and sounds.
- SoundSentry—display visual warnings for system sounds.
- Notification—Get sound or visual cues when accessibility features are turned on or off.
- Text-to-Speech—Hear window command options and text read aloud.
Keyboard and Mouse:
These features are designed to make the keyboard and mouse faster and easier to use.
- Double-Click Speed—choose how fast to click the mouse button to make a selection.
- ClickLock—highlight or drag without holding down the mouse button.
- Pointer Speed—set how fast the mouse pointer moves on screen.
- SnapTo—move the pointer to the default button in a dialog box.
- Cursor Blink Rate—choose how fast the cursor blinks—or, if it blinks at all.
- Pointer Trails—follow the pointer motion on screen.
- Hide Pointer While Typing—keep pointer from hiding text while typing.
- Show Location of Pointer—quickly reveal the pointer on screen.
- Reverse the function of the right and left mouse buttons—reverse actions controlled by the right and left mouse buttons.
- Pointer schemes—choose size and color options for better visibility.
- Character Repeat Rate—set how quickly a character repeats when a key is struck.
- Dvorak Keyboard Layout—choose alternative keyboard layouts for people who type with one hand or finger.
- StickyKeys—allow pressing one key at a time (rather than simultaneously) for key combinations.
- FilterKeys—ignore brief or repeated keystrokes and slow down the repeat rate.
- ToggleKeys—hear tones when pressing certain keys.
- MouseKeys—move the mouse pointer using the numerical keypad.
- Extra Keyboard Help—get ToolTips or other keyboard help in programs that provide it.
The Accessibility Wizard is designed to help new users quickly and easily set up groups of accessibility options that address visual, hearing and dexterity needs all in one place. The Accessibility Wizard asks questions about accessibility needs. Then, based on the answers, it configures utilities and settings for individual users. The Accessibility Wizard can be run again at any time to make changes, or changes can be made to individual settings through Control Panel.
Windows Accessibility Utilities:
- Magnifier—a display utility that makes the computer screen more readable by creating a separate window that displays a magnified portion of the screen.
- Narrator—a text-to-speech utility that reads what is displayed on the screen—the contents of the active window, menu options, or text that has been typed.
- On-Screen Keyboard—displays a virtual keyboard on the computer screen that allows people to type data by using a pointing device or joystick.
- Utility Manager—enables administrator-level users to check an accessibility program's status and start or stop an accessibility programs—automatically, if required.
- Speech Recognition—Vista and newer versions of the OS have built-in speech recognition
For more information about how to access these features and utilities in Windows products visit Microsoft's website Windows Accessibility Resources .
For a comparison of accessibility features across operating systems, see the AccessIT Knowledge Base article How does accessibility differ across operating systems? 
-  How can I tell whether a software application is accessible?
-  Windows Accessibility Resources
-  How does accessibility differ across operating systems?