: If your current PC has a genuine Windows 10 Pro license and meets the hardware requirements, you can upgrade to Windows 11 Pro for free via Windows Update Using Old Keys

Some refurbished computers come with a legitimate version of Windows 11 Pro pre-installed.

: Microsoft often still accepts valid product keys from Windows 7, 8, or 8.1 for clean installations of Windows 11, provided they match the edition (e.g., a Win 7 Pro key for Win 11 Pro). The "Academic and Professional" Path

While these keys often work, they violate Microsoft’s Terms of Service. Microsoft can revoke these keys at any time without a refund. You might activate Windows today, and three months from now, find your license invalidated.

The activation process involves entering the product key into the Windows settings, which then connects to Microsoft's servers to validate the key. Once validated, the user can access all features of Windows 11 Pro.

Microsoft does not provide support for pirated versions of their software. Users of free product keys might find themselves without assistance when encountering issues.

The most reliable way to activate Windows 11 Pro without paying is by leveraging existing licenses or official Microsoft programs.