Most users of new computers with Windows XP pre-installed will notice that no activation is required after they unwrap and start up the new laptop or notebook PC, even though they need to go through the initial set up process, and a product key is found on the Certificate of Authenticity attached to the PC (COA Key). Large PC manufacturers known as Original Equipment Manufacturers (OEM) have the ability to pre-activate Windows XP operating system installed on new PCs via SLP (System Locked Preinstallation).

OEM SLP activation works offline, which means it does not need to contact Microsoft’s activation server to validate the product key and activate the operating system subsequently. However, in pre-activated OEM computers, if the end-user decide to reinstall Windows XP via a clean Windows XP CD which is not supplied by the vendor or manufacturer in order to remove crapware or unwanted software installed by OEM or has lost of original OEM recovery CD, the installed Windows XP is no longer automatically activated. Instead, user has to use COA key to activate. OEM pre-activation also may not work even with original OEM recovery CD after the replacement of a defective motherboard.

To make matter worse, Microsoft has disabled online activation for COA Keys that are attached to PCs that have been pre-activated by OEMs, though most OEM systems use royalty OEM SLP product keys for activation. However, Microsoft has provided a guide for licensed end-users that can preserve OEM pre-activation when reinstalling the operating system using any of the four scenarios outlined below (sysprep, OOBEinfo, manual and unattended) to create a pre-activated Windows XP installation image.

Instant and immediate OEM offline activation of Windows XP requires several requisites to present. The main requirement is existence of SLP 1.0 related magic string in the BIOS, which is validated by the cryptographically signed 4 OEMBIOS.* files which only exist on SLP-enabled OEM CD media from manufacturer. For information, each Windows XP CD or image is valid only for either retail, OEM or volume channels, and each OEM CD is valid for specific manufacturer.

Thus, in order to reinstall Windows XP and preserve the already-activated activation status automatically as OEM computer, the installation media must be of OEM channel and SLP-enabled by same manufacturer. And some of the below methods are meant for IT professionals and experts who want to create Windows XP custom installation image for deployment, and may not work after reinstallation with standard retail Windows XP CD or ISO image.

Tip: Backup OEMBIOS.* from C:\Windows\System32 folder and then retrieve the manufacturer’s specific OEM SLP key from existing system with product key viewer in case the official method does not work, or you can’t get a correct OEM Windows XP installation CD. The SLP key should work across brands with the correct OEMBIOS files. Restore the backed up OEMBIOS files after installation.

OEM-SLP Product Key from Microsoft for Windows XP OEM Activation

Windows XP Professional x86 32-bit: MVF4D-W774K-MC4VM-QY6XY-R38TB
Windows XP Tablet PC Edition: XT67V-GY7FW-GR6FR-WDK2C-8T97J
Windows XP Professional x64 64-bit: FM634-HJ3QK-6QVTY-RJY4R-XCR9J

Note: Windows XP Home edition is not been revealed publicly by Microsoft. However, actual product key from any SLP-activated installation of XP Home can be used on any other, regardless of brand.

Method 1: Using “sysprep –reseal –mini” Command

OEM pre-activation can be preserved when Sysprep.exe is run to reseal the system using the –reseal – mini switches by following these steps.

  1. Download Windows XP Service Pack 1 Deployment Tools.
  2. Extract the downloaded xpsp1DeployTools_en.cab file, and copy the following three files to C:\Sysprep folder:

    sysprep.exe
    setupcl.exe
    factory.ex

  3. Create a file named sysprep.inf using a text editor such as Notepad that contains the information shown below substituting the appropriate product key.

    [UserData] ProductKey =”XXXXX-XXXXX-XXXXX-XXXXX-XXXXX”

    Replace XXXXX-XXXXX-XXXXX-XXXXX-XXXXX with actual OEM-SLP key matching the installed Windows XP edition listed above.

  4. Save the sysprep.inf file in the C:\Sysprep\ folder.
  5. Run C:\Sysprep –reseal –mini.

Method 2: Making changes to the OOBEinfo.ini file

OEM pre-activation can be preserved if changes are made to the OOBEinfo.ini file by ensuring that the %SYSTEMROOT%\system32\oobe\oobeinfo.ini file contains the information shown below but substituting the appropriate product key.

[Version] ProductKey =”XXXXX-XXXXX-XXXXX-XXXXX-XXXXX”

Replace XXXXX-XXXXX-XXXXX-XXXXX-XXXXX with actual OEM-SLP key matching the installed Windows XP edition listed above.

Method 3: Manual Install

OEM pre-activation can be preserved when doing a manual installation by inserting the appropriate product key listed above when prompted for a product key by Windows setup. If you run sysprep –reseal –mini following the manual install, you will need to follow the steps outlined in method 1.

Method 4: Unattended Install

OEM pre-activation can be preserved if you use an unattended answer file (Unattend.txt or Winnt.sif) to automate installation by including the information shown below in the answer file substituting the appropriate product key listed above. If you run sysprep –reseal –mini following an unattended install, you will need to follow the steps outlined in method 1.

[UserData] ProductKey =”XXXXX-XXXXX-XXXXX-XXXXX-XXXXX”

Replace XXXXX-XXXXX-XXXXX-XXXXX-XXXXX with actual OEM-SLP key matching the installed Windows XP edition listed above.

For any of the solutions outlined below, you can verify that the OEM pre-activation has been preserved by clicking Start -> Run and typing %SYSTEMROOT%\system32\oobe\msoobe.exe /A and then click OK. If the procedure was successful, a message indicating that Windows has already been activated will be displayed.