Envy reinstall windows 10

[Karen94]

We just had to install a new harddrive in this laptop, Envy m7-k010dx. The unit was sold with windows 10 installed, but the motherboard thinks it is windows 8.1 and we don't have a product key for windows 10. Attempts to install windows 8 with an old copy of windows on disc have gotten only do far. Is there a way to restore windows 10 although the old hardriveis dead? We even have a back from norton, but don't think it would reinstall windows.

Thanks

Karen 

[WAWood]

@Karen94 

Hello;
Allow me to welcome you to the HP forums!

First off, you can't "restore" anything without first having a backup to restore FROM.

Second, since your PC was already running Win10, then it was already registered with Microsoft. You can use this link to download and create Win10 install media, install afresh with that, and once your PC is back online, it will contact Microsoft and automatically reactivate:  https://www.microsoft.com/en-us/software-download/windows10

Good Luck