How can i retrieve a lost Win 7 product key #? Upgraded to Win 10 B4.

I lost my Windows 7 product key. Changed my HDD and clean installed Windows 7. Looked everywhere for the activation code but there is no hope in finding it. What can be done? My laptop manufacturer is useless. I'm not sure if it would make a difference but back when Windows 10 first came out and they where sending this "upgrade now for free" messages, i upgraded. But about 3 weeks later, i downgraded back to Windows 7.

If you have a Windows 7 install with the current product key, try this: KeyFinder | Magical Jelly Bean

There are other tools as well, but try that first.

If you installed win10 and signed in with a MS account it will activate as the key is stored on their server

F22 Simpilot said:

If you have a Windows 7 install with the current product key, try this: KeyFinder | Magical Jelly Bean

There are other tools as well, but try that first.

I'n not sure i understand. I do have Win 7 installed, but with no product key - therefor a trail version.
I've changed my HDD. The old HDD is the one with the activated Win 7. But that HDD is not working.
The app you suggested "KeyFinder", how exactly will it retrieve the product key since i've never used it in this HDD?

samuria said:

If you installed win10 and signed in with a MS account it will activate as the key is stored on their server

I heard about that. But currently im using Win 7. I downgraded back to Win 7 after using Win 10 for a while. I liked win 7 better.
Do i have to install Win 10 again in order to be activated? And then what...got back to Win 7? And if i do that, will Win 7 then be automatically activated? Is there an easier way to do it? Like without installing Win 10.

SIW2 said:

If the machine originally came preinstalled with win7, then you can run 7oemistaller - the third section
>here<

My antivirus is detecting a virus when i go to install it. Why is that?

SIW2 said:

False positive. Some a/vs do that because it queries the bios.

SIW2!! Thank you! Thank you! THANK YOU!! Worked beautifully!