Microsoft is offering "Microsoft Windows 8 Professional Upgrade" at a discounted price compared to the OEM version. However it states:

If you currently have a personal computer running Windows 7, Windows XP or Windows Vista then you can upgrade to Windows 8 Pro (Professional).

My question is what happens to the Windows 7 key that I use to upgrade? Will it become the Windows 8 key or will it generate a new Windows 8 key?

Basically if I upgrade using my Windows 7 key from my laptop for my desktop will I be able to continue using the laptop on Windows 7 while concurrently using Windows 8 upgrade on my Desktop?

  • Are you asking about a regular upgrade or one of the free-upgrade offers that manufacturers are doing for those who buy a system just before a new version of Windows is released? – Synetech Oct 25 '12 at 19:27
  • This question has a good answer, and one that hints at a likely answer for the general case of upgrading from Windows X to Windows Y. But in some ways it's a very specific answer, and doesn't cover the general case. – mwfearnley Aug 28 '15 at 19:18

When you use an upgrade version of Windows, you need to have a valid licence for a previous, eligible version of Windows. That licence is not freed up for use on another computer after the upgrade.

From the Windows 8 EULA (source: ZDNet):

The software covered by this agreement is an upgrade to your existing operating system software, so the upgrade replaces the original software that you are upgrading. You do not retain any rights to the original software after you have upgraded and you may not continue to use it or transfer it in any way.

Specifically, note the last sentence - you may not continue to use [the old Windows licence] or transfer it in any way. This means that if you use your Windows 7 licence on your desktop to upgrade to Windows 8, you cannot continue using it on your laptop, or indeed anywhere. It's now essentially a part of your Windows 8 licence, though not permanently - if you reinstall Windows 7 and activate with your old product key, you can then use the upgrade licence on another computer.

The same terms applied to previous Windows versions as well. For instance, from the Windows 7 EULA (source: Microsoft):

15. UPGRADES. To use upgrade software, you must first be licensed for the software that is eligible for the upgrade. Upon upgrade, this agreement takes the place of the agreement for the software you upgraded from. After you upgrade, you may no longer use the software you upgraded from.

On a somewhat related note, if your Windows 7 licence came with your laptop (in other words, it's an OEM licence), then you're not even allowed to use it on your desktop - OEM licences are permanently tied to the hardware (specifically, the motherboard) they were originally sold with or first activated on.

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    You could if you wanted ( this is allowed by the license ) install Windows 7 over Windows 8 and install the Windows 8 upgrade on some other computer. The Windows 8 Upgrade can be moved around. Its only the OEM licenses that cannot be moved around. Only a single computer can use an upgrade at any given time. Please understand the installer will let you but eventually one of the computers will be flagged as not being legit ( likely even if they are exactly the same ) since the hdd serial is likely taken into account. – Ramhound Oct 12 '12 at 19:26
  • @Ramhound Good point, thanks. I'll update my answer to mention that the upgrade licence doesn't permanently tie up the previous licence. – Indrek Oct 12 '12 at 19:34
  • Its a trade off. In the past you would pay more to transfer the license around, with Windows 8, because only the System Builder will be sold at retail thats not really possible. Of course the cost is not reduced by several factors. There are very few people who will use a single license across several computers in the course of 2-3 years. – Ramhound Oct 12 '12 at 19:38
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    There's an analysis of the Windows 8 license at zdnet.com/… – David Marshall Oct 12 '12 at 23:08
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    @Moab I'm not sure I follow. To the best of my knowledge, nothing special happens to your old product key. It's not blacklisted or deactivated. If you restore your old pre-activated Windows 7 install, then that essentially deactivates your upgrade key and frees it up for use on another computer, if you so desire. Bottom line is, as long as you're using a Windows install activated with the upgrade key, you're not allowed to use a different Windows install activated with your old key. Does that clear it up? – Indrek Oct 26 '12 at 23:24

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