"I've always been motivated by the desire to meet a deadline. Setting and reaching deadlines gives me such a sense of accomplishment. I love creating an organized schedule for completing tasks and achieving my goals on time. For example, when I ran a marketing event last year, I set multiple deadlines for a variety of tasks leading up to the event. Achieving each milestone motivated me to keep working and helped me to ensure that the event ran smoothly."

Your reply to the motivation question tells the interviewer how you would fit in with the company culture. Prior to your interview, take some time to research Microsoft and the specific job that you're interviewing for. Learn about Microsoft's values and use them as a guide for answering the question: does Microsoft take pride in its staff's problem-solving abilities and teamwork, and If so (and if that matches you) then that would make for an excellent response to the what motivates you.