Microsoft is facing a security crisis affecting approximately 400 million Windows 10 users, as security updates will cease in ten days for those not enrolled in the extended support program. Windows 10 holds a 41% share of the global PC market, down from 46% in September, with nearly 600 million PCs in use. Users unable to upgrade to Windows 11 due to hardware requirements must either pay a fee or follow specific steps for a complimentary extension. Advocacy groups warn that the rapid phasing out of Windows 10 poses significant cybersecurity risks, as vulnerabilities may lead to ransomware attacks after updates stop. Additionally, there is a noted increase in Windows 7 usage, with nearly 140 million PCs still running the retired system. Users are urged to enroll in the Extended Security Update program or upgrade to Windows 11 to protect their data and system security.