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:
No MSDM table = No UEFI BIOS Embedded OEM SLP Key:
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):
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:
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.
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.
Besides pricing there should be no difference between that Edition and Windows 8.1 Pro. Skip the Product Key and select Windows 10 Pro during installation. See if Windows 10 Pro is activated. Otherwise try to clean install Windows 8.1 Pro and then perform an in place upgrade install (or generate a genuineticket file):
https://dellwindowsreinstallationguide.com/the-initial-clean-install-of-windows-10-using-a-faded-windows-7-oem-coa/
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?