Windows 10: How to reinstall windows10 without the product key?

I had windows 10 on my computer i asked a friend to disable my touch screen. He back dated my computer to before i installed windows 10. I no longer know where the product key is. So is there a way to reinstall my windows 10?Thanks

:)

 

Windows10 requiring product key


Is your Windows 7 activated? If it is properly activated a Windows 10 upgrade should not ask for a product key.

Have you tried the "Upgrade this PC now" option of the Windows 10 Media Creation Tool?
Windows 10

After you get a successful upgrade, and the Windows 10 is activated, then you can do a clean install by booting from a Windows 10 USB or DVD which you can also make with the Media Creation Tool. A clean install will ask for a product key and you click on the tiny text that says Skip the step. Might have to skip the Product Key two or three times. IF the upgraded Windows 10 on the same computer was activated, the clean install of Windows 10 will activate. And remember - you have to stay with either the Home or the Pro version - you can't go from Home to Pro or from Pro to Home.

 

Windows10 requiring product key


Please help, I had windows10 "successfully" installed. However, I had to while my hard drive and install windows7 home premium again...now if I try to reinstalled windows10 from there website it now asks me for a product key. Also I have waited, upgraded and allowed the PC to do its own updates etc..but still no windows10 notification in bottom right corner..hope somebody can help me, many thanks

 

Product Key for Windows10 free upgrade from Windows7 Home premium

I have today upgraded my Windows 7 to free upgrade package of Windows10. Now for activating Microsoft Office in Windows10 the earlier key provided with my Windows7 is not working. Since this is a free upgrade I do not have a product package. So please
let me know how to find my new product key for the newly upgraded Windows10.
And how to

• Create a Windows 10 DVD for installation on a new hard drive
• Create a backup Windows 10 DVD
• Create a bootable USB drive with a copy of Windows 10
• What is clean reinstallation? Is it necessary after free upgradation?