Question about Microsoft Windows 10 Pro

OEM license. The OEM (Original Equipment Manufacturer) licence for Windows is the cheapest but also the most restrictive licence. ... The big drawback of the OEM license (which explains its low price) is that it is tied to your machine for life, so it is impossible to move the license to another PC

The oem version is always installed on the same PC, (in case of problems) with an update but without help from microsoft, and the retail version is more expensive or (boxed) for several PCs with an update and help from microsoft if there are big hardware problems.