Are you installing this on a or just refreshing an old laptop ?
You do not need to search for a specific "Windows 10 Pro ISO." You download the standard ISO from Microsoft. During the installation process, you will be asked, "Which edition do you want to install?" Select Windows 10 Pro at that screen. Windows 10 Pro Iso 64 Bit Download Microsoft
Microsoft does not provide a direct "click-to-download" button for the ISO on Windows PCs. Instead, you use their official utility: : Go to the Windows 10 Download page. Are you installing this on a or just