MICROSOFT TURNS 50! HERE ARE ITS 25 MOST IMPORTANT PRODUCTS & MILESTONES

OUR RETROSPECTIVE LOOKS BACK AT THE EVENTS THAT SHAPED MICROSOFT'S HISTORY, AS TOLD BY PCWORLD AND OTHERS.

- BY MARK HACHMAN

Microsoft has arguably done more to shape the evolution of the PC than any other company. It celebrated its 50th anniversary on April 4, 2025. Fifty years is a long time for anyone, let alone a business that has driven itself to move at the pace of the computer, then the internet, and now artificial intelligence. That's decades of decisions, launches (and lawsuits!), and apps both good and bad. Many changed how you live and work.

Which ones stand out most? Here are 25 key moments in the long, storied history of Microsoft. For each, you'll find a bit of background, a quirky fact or two, and what it has all meant for Microsoft and for you. Happy birthday, Microsoft!

1975: GATES AND ALLEN SHOW OFF THEIR BASIC INTERPRETER

In Albuquerque, New Mexico, Bill Gates and Paul Allen met at Lakeside School, forging a partnership that would literally change history. The Lakeside Mothers Club bought a teletype that could connect with a General Electric timeshare computer, and Gates honed his BASIC skills while using it. He even wrote a computerized class schedule (fave.co/4j6Gule) for Lakeside, scheduling a "disproportionate number of interesting girls" alongside him in class. (Ahem.) At night, he read computer manuals.

In 1975, the MITS Altair 8000 debuted, and Gates and Allen decided to write a BASIC interpreter for it after reading about it in Popular Electronics. In March 1975, they convinced MITS that the interpreter worked, and that MITS should distribute it as Altair BASIC.

Gates and Allen established Microsoft on April 4, 1975, the same day Altair BASIC was released. “Micro-Soft” was registered on Nov. 26, 1976, asa pastiche of “microcomputer” and “software.”