Some technician told my lady to downgrade her Lenovo G50 from Windows 10 to Windows 7 a couple years ago, and he did this for her. Now we're looking into upgrading it back to Windows 10. Back in the day, computers used to ship with a reinstallation CD, but today, sadly, this process is now much more cumbersome and time consuming since computers no longer ship with the CD/DVD.

I was thinking I have the following options, after backing up the data:

  1. Dual boot Windows 7 and a newly installed Windows 10 and then contact Microsoft to get the OEM Windows 10 activated using the computer's serial number linked to the OEM Windows 10 installation. If the Windows 10 license is invalid or we're unable to activate it, we still have Windows 7 and can delete the Windows 10 partition. If Windows 10 activation is successful, we can either keep Windows 7 or delete it.

  2. Reinstall Windows 10 only. If we cannot get an activation code from Microsoft for the OEM Windows 10, we lose both Windows 7 and Windows 10 and will be forced to pay for another copy of one or the other.

  3. Install some Linux alternative. The user of the laptop is not a tech person and needs to use educational software such as Zoom, Powerpoint, and other educational and communication tools, so this is likely not a good option.

I'm thinking option 1 is the safest bet since we keep the somewhat working yet deprecated Windows 7 installation, keeping the laptop in a somewhat usable state in the event that product activation for Windows 10 fails.

I was also thinking that there may be a hidden partition on the Lenovo G50 for reinstalling Windows 10, but I'm not sure how to verify if it is there or not considering the technician manually reinstalled Windows 7 and may have wiped it. Also, I'm not sure if it's possible to access that partition from Windows 7, considering the factory operating system was Windows 10.

The big question is what option should we choose to get Windows 10 back on the laptop? Where can we obtain a Windows 10 ISO? Is it possible to reinstall, and if so, what steps should we follow?

  • Windows 10 doesn’t require an “activation code” or a “license code”, in order to reinstall Windows 10, you simply install it. When the installation is complete, after you create the first user, Windows 10 will automatically activate.
    – Ramhound
    May 21, 2020 at 5:01
  • 2
    Does this answer your question? Where can I get a clean ISO of a specific build of Windows 10?
    – Ramhound
    May 21, 2020 at 5:02
  • @Ramhound Yes. Thank you. I downloaded the iso. It now looks like I either need to create a bootable USB or burn a DVD.
    – jmort253
    May 21, 2020 at 5:12
  • I still have concerns about going back to Windows 7 if the Windows 10 installation fails for some unknown or unexpected or unaccounted for reason. Maybe in that case it's just a sign to get a new computer...
    – jmort253
    May 21, 2020 at 5:14
  • If the upgrade to Windows 10 fails it will automatically rollback to Windows 7. It’s not possible to “lose” a Windows license. Furthermore, you made no mention, of trying to upgrade your current installation. You are worrying about nothing. How you reinstall Windows 10 on an OEM machine has been answered by some of my existing answers.
    – Ramhound
    May 21, 2020 at 5:38


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