It is often thought that a graphical interface such as Windows, with its pictures and "icons", is inaccessible to those without vision. In fact these operating systems are still, in reality, text-based and often pictures are purely cosmetic or accompanied by a text label.
A blind computer user can know what is on the screen by having the necessary information spoken by a synthetic voice. This could include having each character or word echoed back as you type. On computers that can produce sounds and music the speech output can be produced in a similar way, through the main speakers. In other instances a separate piece of equipment may be required to make the computer talk.
The software programs that control the speech (called "screen readers") vary in their reliability and intelligence. The more sophisticated allow the user effective and reliable "eyes-free" use of the vast majority of DOS or Windows 95/98/NT programs (as well as some running under other operating systems).RNIB factsheet: What is a screenreader Accessing the web with a screenreader