This question can be answered in many different ways. In light of this, let me give you a number of ways in which computers have changed our society.
First, computers have changed the way information is saved and accessed. Now with a few clicks on a computer, people can access almost any piece of information. The speed at which people can access information has never been faster. We can say that the computer has democratized almost all information. This point cannot be overemphasized.
Second, computers have changed warfare. Now people use computers to conduct war in many ways. The threat of cyber-warfare is real and even within the past few years, many hackers have tried to break into our military systems. This area will certainly grow in the future.
Third, on a less serious note, computers have changed shopping and advertising. People are buying more on-line and advertisers are using on-line advertisement more to reach people.