Windows 7 OEM SLP

DellWindowsReinstallationGuide is written and maintained by Philip Yip.



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Windows Installation Media

Windows 7 Factory Settings utilise OEM System Locked Preinstallation (SLP) as an activation mechanism. For Dell (or any other major OEM) Systems the BIOS of the motherboard contains a System License Internal Code (SLIC). The OEM factory image or OEM Installation Media is setup to look for said SLIC and activates if it finds it. For Windows 7 the SLIC has to be version 2.1. Systems shipped with Windows 8.x Pro OEM and Windows 10 Pro OEM also contain a SLIC version of 2.1 for Downgrade Rights. In the past OEM Installation Media wasn’t downloadable but Dell have recently rectified this for Business models with the Dell OS Recovery Tool c.f. the Dell Windows 7 Professional Skylake Reinstallation .iso.

For other Editions of Windows 7 or for other OEMs, OEM installation media is hard to come by. The Windows 7 Retail Installation .iso on the other hand is readily downloadable from Microsoft. By default Retail Installation Media completely ignores the presence of a SLIC instead asking for a key to activate. The rest of this guide will instruct on the application of OEM SLP with Retail Installation Media.

Edition and EI.cfg

The only file that differs in all the Retail .isos and Commercial OEM .isos is the EI.cfg file. This file locks the installation to a specific Edition of Windows 7.

Delete the EI.cfg file from the sources folder of your Bootable USB to get the option to install all the Editions of Windows 7 present on the .iso.


You should install the correct Edition of Windows 7 matching your COA:

Windows 7 COA

This is often found under your battery compartment to reduce the likelihood of fading:

Laptop COA

Alternatively you should install Windows 7 Pro if you have the following stickers:

win10Pro Win8Pro

If you have stickers like the above but without Pro you do not have OEM Downgrade Rights and this guide will not work for your hardware.

The Product Key?

Retail Installation Media will ask for a Product Key. The Product Key isn’t necessary for standard OEM Activation.

You do not have a Product Key if you have the stickers below:

win10Pro Win8Pro

Or if your COA is faded:

During installation Uncheck “Automatically Activate when I’m online” and select skip:


This will install Windows 7 without a Product Key allowing a 30 day trial.

One can check the Product ID and Activation status in system (go to Start, Right Click Computer and Select Properties). They should see that Windows 7 is not activated.


OEM Cert Collection

You require two files the first is a script and the second is a certificate. The script is run through the command prompt to install the certificate. Once the certificate is installed OEM SLP will be applied. These two files are unique for each OEM and Edition of Windows 7 and I put together a collection here which covers almost all OEMs:

Once downloaded right click to Extract the Folder:


Select Extract:


Open the extracted folder:


Select your OEM:


Select your Edition of Windows 7:


Copy the OEM folder:


Ensure the OEM folder is placed directly on your C:\ Drive (if it is elsewhere the script file will fail):


Right click the slp.bat and select Run as Administrator: 13

Accept the UAC prompt:


Press OK – you will be informed that the license file is installed:


Press Ok again – you will be informed that the generic SLP product key associated with the license is installed:


Press any key to continue (this will close the command prompt):


Checking Product Activation

One can check the Product ID and Activation status in system (go to Start, Right Click Computer and Select Properties). Windows 7 should be activated using OEM SLP:


Troubleshooting – Do I Have a SLIC?

If you don’t have a SLIC version of 2.1 this guide will not work for you.

You can use RW-Everything to manually determine whether or not your system has a SLIC.

To determine your SLIC launch RW-Everything and select Access → ACPI Tables:


Select the SLIC Tab:


Scroll down until you get the SLIC Marker Structure. You are interested in 2 fields:

  • OEM ID
  • SLIC Version

In this case the OEM is Dell and the SLIC Version is 2.1 making the system Eligible to Activate using Dell OEM SLP.

N.B. A SLIC Version of 2.0 is eligible for Windows Vista OEM SLP only.