MICROSOFT Windows 10 warning - PC users need to upgrade to latest OS WINDOWS 10 doubters need to upgrade to the newest version of Microsoft’s flagship operating system, and this is why. Windows 10 is the most current version of Microsoft's flagship OS after first launching two years ago. However, despite this it is not the most popular Windows OS out there for PC fans. According to NetMarketShare , Windows 7 is used by more PC users than Windows 10 - with the eight year-old OS having a market leading 47.21 per cent share. This is compared to the second most popular PC OS, Windows 10, which has a 29.09 per cent chunk of the operating system market. While Windows 8.1 and Windows XP have an operating system market share of around five per cent each. However, for the huge amount of PC owners using an earlier version of Windows, they’ve been given a stark warning as to why they need to upgrade to Windows 10 as soon as possible. The Register has reported that Microsoft ha...