I already explained this a little in another question about restarting your career. You can use the same answer here if you want, but I will give one more example of not changing your major in the long answer section.
This answer demonstrates a good choice in the beginning. I included the portion about computers because they want to see something you would have done differently. And making the comment about computers shows the interviewer your understanding about technology to some degree. But don't say this answer without first stating that you are pretty good with the computer.