Windows 7: Is the windows activation key unique? Subject to change? Where is it?

I was told the Product ID is not unique. Is the Key different?
Is it subject to change? And how about a clean install?
Am I correct that that is what is found (encrypted) as DigitalProductId in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion?

I'm not sure as to the registry entry, but the Product ID is not unique to different users. The Product ID is like a model number or version and is used to describe the platform, build, and version of Windows.

The activation key (aka product key) is unique to each person because it's like a "password" to unlock and activate windows, and is not subject to change. If you purchased a computer straight from the manufacturer with Windows pre-installed, there should be a sticker somewhere on your machine with the 25 digit product key listed.

The Product ID is NOT unique
The Product Key may be unique - depending on whether the Key in use is the Key from the COA sticker, or the original OEM_installed Key.
If you do a Clean Install using a Retail or OEM System Builder disk, the Key is ALWAYS unique to you
The Windows Product ID is found in plain text in the registry - the Key is (mildly) encrypted.

I don't understand what you meant by that.

As for the "clean installation" - I meant - what if someone re-installs his OS, does the key change?
Thank you for your answer.

Computers, which are built by large manufactures that come with Windows
Pre-Installed, come with two (2) Product Keys:


A) OEM SLP: This key comes pre-installed in Windows, when it comes from the Factory. This key is
geared to work with the OEM Bios Flag found only on that Manufacturer's computer
hardware. So when Windows was installed using the OEM SLP key (at the factory)
Windows looks at the motherboard and sees the proper OEM Bios Flag (for that
Manufacturer and that version of Windows) and Self-Activates.





B) COA
SLP: This is the Product key that you see on the sticker on the side (or bottom)
of your computer. It is a valid product key, but should only be used in limited
situations (such as if the OEM SLP key stops self-activating for whatever
reason). (Note: All manufacturers that use the OEM SLP system are required by
contract to include a Certificate of Authenticity (COA) sticker, that has a COA
SLP key, on the computer)


The Key is defined by the License - for Pre-installed Windows, the Licenses are OEM (as above). For Retail or Upgrade Licenses, the Key is in the packaging.
It does not change.

The Product ID is the identifier that tells Microsoft whether you have a retail Windows system or an OEM system and the number can change if and when you re-install the operating system.

If you are using retail the ID number will be in this format: xxxxx-xxx-xxxxxxx-xxxxx

If you are using OEM the ID number will look like this: xxxxx-OEM-xxxxxxx-xxxxx

The Product Key is used to tell Microsoft you have a genuine system and it is this that never changes.

In case you didn't know, OEM stands for Original Equipment Manufacturer and under the terms of the license is tied to the first computer the software was installed on.

A retail license allows you to install Windows on another computer providing it has been deactivated and removed from the old computer.

I have a Toshiba laptop in which Win 7 Home Premium x64 came pre-installed. I messed up trying to remove the Toshiba bloatware, and now I'm planning to do a clean install of 7.

For this I backed up the Win 7 activation, but at this point I noticed that the product key which got backed up is different from the one on the sticker at the bottom of the laptop.

Also, there was no OS DVD with the laptop, so I downloaded a copy (retail) from Digital River.

After installing Win 7, I'm planning to restore the activation backup. So should I install using the key I found in the activation backup or the one on the sticker?

You need to use the product key on the COA sticker, as this tutorial explains.

Clean Reinstall - Factory OEM Windows 7

But can I restore the activation after that?

If you use a system restore the probablility is you won't need to re-activate, but if you do it will either do it online with the COA key or at worst phone a toll free number and speak to an agent (of MS not FBI and stuff) tell them what you did and they will give you a code and details how and where to enter it.

Follow the tutorial, it is my experience that peeps like seavixen32 give advice which you really should follow.