Reinstall Win10 but forget deactivate it first

Question

I have product key for Win 7 Pro. I've upgraded to Win 10 Pro. All went great, but after some time I've decided to switch back for Win 7 Pro. So, I've downloaded the image, deleted whole partition, instaled fresh Win 7 Pro and now the system doesn't want to recognize my product key. I guess it's because I've forgot to deactivate it in Windows 10 when I was deleting it.

IS there any way how to get of this situation ? I do not really want to buy another Windows. I am fine with using just Windows 7 Pro.

Thank you

Answer 1

Apparently your online activation limit for Windows 7 was reached and was so marked by the Microsoft license server.

It might be possible to deactivate Windows 10 by reinstalling it from scratch, since it will then be automatically activated by digital entitlement, and then can be deactivated by entering in an elevated Command Prompt the command :

slmgr /upk

However, I don't know if this will decrease the online activation limit for the Windows 7 key with which you originally upgraded to Windows 10.

Failing that, I suggest to phone Microsoft Support, explain your problem and supply a proof of purchase for the Windows 7 Pro product key. You should be using Windows 7 with SP1 for getting support.

Support might give you a new key for activating Windows, or alternatively can always bump up or reset the online activation limit of your existing key. Windows 7 is currently on extended support, so Support will answer.

But I strongly advice staying with Windows 10, unless this presents unsolvable problems. Windows 7 is not very secure when compared with Windows 10.