If you are trying to install Windows 11 on an older PC, you have likely encountered the "This PC can't run Windows 11" error due to missing TPM 2.0 or Secure Boot. While Microsoft officially requires these for security, there are well-documented registry workarounds used by enthusiasts to bypass these checks during installation.
This method is used when you are booting from a standard Windows 11 installation USB. You can perform these steps as soon as the installer informs you that your hardware is unsupported.