The OEM Product Key and OEM System Locked Preinstallation

Your Original Equipment Manufacturer (OEM) Product Key

Genuine Microsoft Label and Microsoft Digital Marker

Newer systems come with a Genuine Microsoft Label (GML) like the following:


These labels just indicate the presence of a Windows License. The 25 digit System Locked Preinstallation (SLP) Product Key resides with a Microsoft Digital Marker (MSDM) Advanced Configuration and Power Interface (ACPI) table embedded in the Unified Extensive Firmware Interface (UEFI) BIOS.

The correct installation media discussed below will automatically input this SLP key during installation and you shouldn’t need to manually look it up to input it. The UEFI BIOS ACPI Table MSDM tab can be checked with RWEverything.


In the rare case you have an issue with RW-Everything hanging when trying to open the ACPI tables contact Jeff RW-Everything Contact.

You may also use the Windows Product Key Tool to obtain your UEFI BIOS Embedded SLP Key from your MSDM tab:

product key utility - Copy

No MSDM table = No UEFI BIOS Embedded OEM SLP Key:

product key utility

Code of Authenticity (COA)

In the past systems shipped with Windows 7 OEM will have a code of Authenticity (COA). This is a paper label which contains your Edition of Windows alongside your 25 digit OEM Product Key. This Product Key can be used with Windows 10 Installation Media but is not typically used for Windows 7 installation (see System Licensed Internal Code):

Windows 7 COA

Since the launch of Windows Vista the COAs provided by Microsoft have been of low print quality. In order to reduce their likelihood of fading OEMs typically placed them under the battery compartment in laptops. Use your phone to take a picture of the COA before Windows 10 installation:

Laptop COA

System Licensed Internal Code (SLIC)

For Windows 7 OEM there was also a BIOS based activation mechanism. The System Licensed Internal Code (SLIC) Advanced Configuration and Power Interface (ACPI) table is embedded in the BIOS. The BIOS ACPI Table SLIC tab can once again be checked with RWEverything.


A SLIC version of 2.1 is eligible for Windows 7 OEM System Locked Preinstallation. A SLIC Version of 2.0 is for Windows Vista (End of Life) and a SLIC Version of 1.0 is for Windows XP (End of Life).

OEM branded installation media such as the Dell Windows 7 Reinstallation DVD will install Windows 7 OEM with a generic System Locked Preinstallation (SLP) key. If the SLIC and OEM ID match the SLP key and Windows Edition then offline product activation will occur.


3 thoughts on “The OEM Product Key and OEM System Locked Preinstallation

  1. I bought a device on eBay and although using RWEverything I was able to see that the MSDM is present with the Product Key there I still wasn't able to install Windows 10.

    When I went to Dell Support and entered the service tag I saw:

    Windows 8.1 Pro 32bit National Academic. K-12 EDU use only. MSFT LOE Approval reqd. DM English

    So that may have been the reason why it didn't work.

  2. We will be receiving several identical systems from Dell with pre-installed Windows 10 Pro OEM. I would like to configure one unit with all the necessary software, image it and restore the same image to all the others. It seems that I cannot do this unless I have a volume license from Microsoft. Could I not get the OEM license of each system and then re-install the OEM serial after the restores?

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