Windows 10: Can't find Original Product Key - Upgraded from 7/8 to 10

So basically I bought windows 7 or 8 (can't even remember) and I used my university email back then. Since then I graduated and I have no longer access to my old E-Mail account and the receipt from Microsoft.

Since then I upgraded to 10 and a few days ago I bought a new PC. I found my windows key on my "old" PC by using 3d party software and activated it on my new PC. After a day I got a message that I have to activate my windows... Apparently the key that I saw is not the "original" key from windows 7/8 because the old key morphs into a new one the moment I upgrade to 10.

Is there any way of finding the original code from an already installed windows or am I forced to buy a new copy of windows?

Thank you.

:)

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Will windows 10 still accept the license keys from 7 and 8 now if I reinstall my computer?

Does Microsoft keep a list of users who upgraded to Win 10 using their 7 and 8 keys so that when users need to reinstall windows 10 the old keys would work?

Do I need to call in Microsoft to ask them to activate my Windows 10 when I give them my win 7 keys?

Both computers are laptops. The windows 7 machine had the serial printed on the back, and I needed to enter that when I upgraded to 10. The windows 8 machine had the serial built in inside its boot system so I didn't need to enter the key when I upgraded to 10, but I did manage to write down the keys using a fetcher program.

 

Windows 7 product key does not work on Windows 10

In case of a hardware change

In situations such as after changing your motherboard, which everybody believes the Windows 10 upgrade license activation process is tied into, you need to

1. Install the original Windows 7/8 again and activate it with your original Windows 7/8 license,
   
2. Either do the Windows updates to get the Upgrade to Windows 10 notification (specifically KB3035583 update), or burn the ISO file for Windows 10 into a DVD and install it (Choose upgrade, not the fresh install) from within your original Windows 7/8. (Note 3)
   

The process above will register your new hardware against your free Windows 10 license (Upgraded from Windows 7/8). Now you can do a fresh install of Windows 10 and skip all the License Key (two of them I believe) during the installation process and it's guaranteed your Win 10 will be active after the end of this process.

Note: Since my Windows 10 was already set up (However showing me no Activated after the hardware change) and in a working state, I have done the steps 1 & 2 on a separate HDD, which lead to registering my new hardware with the Win 10 license and then plugged the original HDD back on with my configured Win 10 and it was activated after this process. Then I didn't need to set up my Windows from the scratch again.

Note 2: I have contacted Microsoft and they couldn't activate the Win 10 on the new hardware and recommended the steps 1 & 2.

Note 3: Be reminded that step two is only going to be active till July 2016 and after that, you won't be entitled to a free upgrade of Windows 7/8 to Windows 10 anymore.

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Yes, still work, no need to call, just be sure to have internet access when you start to install 10, I work at pc shop and did this few days ago, used a key of 7 to put clean 10(wasn't used for upgrade).