The OEM (Original Equipment Manufacturer) key is a type of license key pre-installed on computers when manufactured by companies like Dell, HP, Lenovo, etc.

When referring to the "OEM key", "DM" here abbreviates "Digital Marker", meaning this license key is embedded into the computer's firmware (BIOS/UEFI). This enables the Windows operating system to automatically activate the license when installed on that device, without the user needing to manually enter the key.

Main points about the OEM:DM key:

• Embedded in firmware: The license key is directly integrated into the computer's BIOS/UEFI.
• Automatic activation: Windows will automatically recognize and activate the license when reinstalled on that computer.
• Tied to hardware: The OEM key is tied to the computer's hardware, and changing the motherboard may result in losing the license.

Thanks to this mechanism, users will have a more convenient experience when reinstalling the operating system, without worrying about finding and entering the license key.