For instructions on how to downgrade properly, just contact your PC manufacturer. The OEM license of Windows 10 Pro allows the legal downgrade to a previous Pro version of Windows (Windows 7 Pro, Windows 8 Pro, Windows 8.1 Pro). Only System Builders can, through a national distributor, (list at the bottom of the article) have access to these types of contracts to integrate license keys on PCs. It cannot be sold separately and the only way to have it is combined with a PC. For computers that are born with Windows 10, we find only a Microsoft holographic stamp of originality in front of the PC, without the license key. Often System Builders always use the same Windows 10 code (see DELL, ASUS, ACER etc.). These license keys are digital and integrated into the BIOS of the computer together with the serial of the PC. It is only used by System Builders with Microsoft. The true OEM (Original Equipment Manufacturer) license is a license sold with the PC. There is a lot of confusion about this license and it is often confused with the OEI license.
