More than 8 in 10 desktop computer users in the world are using Microsoft operating systems. The company may not have the same obsessive fans of rival Apple, but for sheer market share, Microsoft is clearly in the lead, with more than a billion users worldwide. And it may seem like Windows has been around forever, but it only feels that way. The first version of the operating system was released about 30 years ago, just before the company went public for the first time. Learn more about the company, its blockbuster operating system and other programs and products Microsoft has developed.