Windows XP
Microsoft invested $1B in marketing when it prepared to ship Windows XP. When the operating system was released in 2001, it was many people's first experience with a home computer. Windows XP introduced a suite of features that made using a computer accessible: a standard user interface, easy software updates over the internet, and faster app switching.
OS marketshare, 2020
Around the world, 140 million computers still run Microsoft XP, including millions of ATMs. According to GlobalStat's Stat Counter as of May 2021 0.7% of Windows PCs worldwide run Windows XP (4% in Africa). Microsoft officially stopped offering support for the operating system in 2014.