My situation is as follows: I have three license keys for Windows:

  • (A) 1 Windows 7 Professional
  • (B) 1 "Microsoft Windows 7 Professional with Service Pack 1 32/64-bit (German) - DreamSpark"
  • (C) 1 Windows 7 Home Prem OA

Now I had a computer that ran with my (A) license for some years, anyway last month I bought a new laptop which I will use instead of the computer. The laptop came with license key (C), but since I didn't want all programs and the stuff that comes with a new Windows on it, I formatted it, using my (A) product key.

In hindsight, that was not such a brilliant idea as I now see, because apparently I cannot use the older license (A) for the activation of my new laptop, since it is already connected to the old PC.

But I have got license (B) from my university which offered a free license for every student, I requested (B) about one month ago. Nobody ever used it and I didn't share it with anyone. Now it appears as if it is not compatible with my current version of windows on my laptop, although both are Windows 7 Professional. When I try to activate my product by changing the laptops' product key to (B), I get the error message that this key is not a valid key DESPITE the fact, that I copy-pasted it from the Dreamspark page where I got it from.

So there is no possibility of misspelling or anything, what could be the reason for the problems I have?

EDIT: I just want to get my laptop run with a valid product key without re-formatting it. If there is a possibility to get (C) running via an upgrade or something, I really don't care which Windows7 I will use. Fact is, that I have 3 product keys, but the laptop is not activated, which I want to change.

  • It it accepting the keys as valid but not activating or is it saying the keys are not valid at all (or are you asking where to enter the keys in the first place) Feb 5, 2013 at 22:57
  • It says the license B is not valid at all, although I "bought it" online from the dreamspark page, though I didn't pay for the license since every student gets one license key free.
    – Dennis K.
    Feb 5, 2013 at 23:10

2 Answers 2


The licence keys are specific to each version. You can't use a key from one to activate another. Although A and B both represent Windows 7 Professional, they are almost certainly different versions. That is the reason for the B key being not valid. To clarify, it is a valid key, but not for version A - it is only a valid key for version B.

You can't upgrade to C from A as A is already an upgraded version of the OS (pro/home). It would be a downgrade and AFAIK this is not possible.

The only way you can do this is via manual activation on the new laptop of licence A to transfer it. However this will deactivate the old computer.

There is no way to have both machines activated using the same OS whilst using keys from differing versions.

Unfortunately your best bet would be to back up your personal files and then re-install that actual OS that you have a free key for.

  • Thanks for the quick answer, what would be the steps to transfer the license key A to my laptop? My Google results were more of the "you can only use a license for ONE computer, it is not transferable!" kind. If you have a link or more infos on how to transfer the key, I'ld be most thankful!
    – Dennis K.
    Feb 5, 2013 at 23:06
  • Did windows come with the laptop or did you install it at a later date. and if you did install it at a later date is windows a OEM version? Feb 5, 2013 at 23:21
  • As I described in the question, the laptop came with Windows (C) installed, which is not a OEM version, and later on I installed the Windows (A), which is also not an OEM version.
    – Dennis K.
    Feb 6, 2013 at 0:20
  • 1
    @DennisK. To transfer the licence simply go through manual activation on the laptop. This usually involves calling an automated service. The options change, but essentially you have 'substantially changed the hardware' and only 'have the software activated on one machine'. The automated service will then generate you an activation key for the laptop. As I mentioned, once you do this the older pc will show as un-activated if you try to do updates etc. To be clear, you can only have the 'key' activated on on machine at a time, but it can be a different machine than the original old computer.
    – Fraser
    Feb 6, 2013 at 0:46
  • 1
    @DennisK. Also, you aren't 'transferring' the licence in the same sense. Think about it, what if I replaced the motherboard, processor, ram, hard-disks, case, etc - in any combination or all at once - is it the same computer? All you have done is bought all those separate parts in one box - it isn't the same computer but that doesn't matter. You haven't transferred the licence to someone else and you are going to use it for ONE computer so that is all OK.
    – Fraser
    Feb 6, 2013 at 1:03

The problem is solved without transfering the license key or re-formatting my laptop:

It appears that the problem existed in the fact, that the current product key A was a key for the Windows 7 Professional, in contrast to B, which was a key for Windows 7 Professional with Service Pack 1.

It seems impossible for Windows to detect the fact that both are in fact the same OS unless I have the Service Pack 1 installed. Now the solution was this:

  • I installed the Service Pack 1 to my Windows 7 Professional, let it pass the configuration and waited until it was ready and logged in.
  • After that, I tried to activate the system with the license key B again (for Windows with Service Pack 1) and it was able to activate the product online.

Long story short: A is not equal to B, but with the installation of Service Pack 1, the current version of Windows became compatible with B, so I got it activated.

Thanks anyway to everyone who helped in comments or answers!

  • glad it worked out for you.
    – Fraser
    Feb 6, 2013 at 9:16

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