Windows 11 requires a 1GHz dual-core CPU that supports TPM 2.0 and at least 4GB of RAM. Users with older PCs running Windows 10 can still install Windows 11 25H2 using known bypass methods, even if their hardware does not meet these specifications. The installation methods include using a command line for an in-place upgrade, utilizing Rufus to create a bootable USB, or editing the Registry during setup. The Windows 11 ISO file is approximately 7.20 GB in size and can be downloaded from Microsoft's official site. Users can revert to Windows 10 by navigating to Settings > System > Recovery and selecting "Go back."