Microsoft is alerting Windows users about a significant cyber threat as many PCs will stop receiving essential security updates. A free upgrade to Windows 11 is recommended, which offers enhanced security, but 240 million users remain at risk. Microsoft encourages users with outdated PCs to transition to Windows 11, which requires a TPM 2.0 security module. As of April, Windows 11's adoption has reached 44%, while 53% of users are still on Windows 10, though this percentage is declining. The gap between Windows 11 and Windows 10 usage has narrowed to within 10%. Users unable to upgrade may face security risks and should consider safer alternatives, including transitioning to passkeys instead of passwords for their Microsoft accounts.