Hi @Evgenyi
Welcome to the HP Forums!
This is a wonderful place to converse with the community, get assistance and find tips.
I reviewed your post and understand that you want to know if you performing recovery from the D drive will it bring back Windows 8 on the computer.
I’d love to help!
As you have upgraded the computer to Windows 10, I am not sure whether you can perform recovery from the D drive as usually after upgrading to Windows 10 the recovery partition doesn’t work.
To answers your question, yes, if you perform recovery on the computer using original recovery media (If you have created one) the computer will go back to Windows 8.
In case you want to install Windows 8 back on your computer you can contact phone support and they will help you order recovery media for your computer and using that you can restore the computer back to its original factory settings.
Here is how you can get it touch with the phone support.
Open link: www.hp.com/contacthp/
Enter Product number or select to auto detects
Scroll down to "Still need help? Complete the form to select your contact options"
Scroll down and click on HP contact options - click on Get phone number.
Hope that answers your question and you have a great day!
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Take care now and have a splendid week ahead.
Cheers!
The_Fossette
I am an HP Employee