Microsoft has ended support for Windows 10 as of last month, leaving hundreds of millions of users vulnerable to security risks. Approximately 1.5 billion PCs are currently in use, with around 500 million capable of running Windows 11 but not upgraded, and another 500 million that are four years old and unable to support the new operating system. Dell's COO has indicated that previous estimates of Windows 10 installations were significantly underestimated. Microsoft is encouraging users to upgrade to Windows 11, which offers enhanced security features and claims a 62% reduction in security incidents. The next critical date for Windows 10 users is October 2026, when extended security updates are unlikely to be available.