Trying to restore windows on my computer (currently running Ubunut).

Hello, I am trying to restore Windows 10 to my computer.

Background:
I was dual-booting Widnows 8.1 (came pre-installed on ACER laptop I recently purchased) and Ubuntu. This worked fine until I decided to take the free upgrade to windows 10 being offered. During the upgrade process, it deleted a partition for Ubuntu and ended up killing both OS. I was stuck with BIOS and had no idea how to restore my computer, particularly with both OS being able to co-exist peacefully.
I only needed to access Ubuntu for work purposes and my boss gave me a copy of both windows 8.1 and windows 10 (stand alone clean install). I did successfully install windows 10 but was not able to dual-boot to Ubuntu. Because I needed to prioritize work, I scrapped windows 10 and currently only run Ubuntu.

Good news, I quit my job and no longer need or want Ubuntu! I simply want to go back to the way things were meant to be and have my functioning windows 10- no dual booting. My questions are these: How do I restore my system to its original condition (with windows 8.1, if it still exists somewhere in my motherboard that is)? Considering that I am currently running Ubuntu, what do I have to do to make this successful (with the intention of getting rid of Uubuntu all together)? If I am unable to restore my system, then I will fall back to installing windows 10 (or 8.1 if that fails) clean; how do I extract my product license key from my system? It is not written down anywhere and windows will prompt me for it if I install from a CD.

Ideally I would be able to install windows 10 clean from my disc, extract and validate my product license key successfully, not having to deal with the upgrade process.

The Windows 8 product key should be in BIOS. What I would do is download the most recent version of Windows 10 ISO from Microsoft Tech Bench, make a bootable Windows 10 install USB or DVD from it, boot the computer from the Windows 10 install USB/DVD. It should read the Windows 8 product key from BIOS and not ask you for a product key. Select custom install, delete all the partitions on the hard drive, select the unallocated space to install to and let Windows 10 do it's thing. The latest version of Windows 10 should activate based on the Windows 8 product key in BIOS. You can view the product key in BIOS using showkey plus from this forum.

Windows 10 download:
Windows 10 ISO Download - Windows 10 Forums
(option 1)

Showkey plus:
Showkey - Windows 10 Forums

If you really want to go back to Windows 8.1 first, you can download it here and it should read the product key in BIOS and install/activate itself:
Create installation media for Windows 8.1 - Windows Help

Thank you. I attempted this but Ubuntu doesnt want to copy the windows.iso file to a USB. I borrowed my friends pc to make the USB key and I discovered that the instructions file contained in the download were VERY confusing. I am going to try booting from the USB now to see if it worked.... if not, then should I try doing it through the creations media tool?

The BIOS isn't picking up the USB drive, "no boot device" detected. I am not sure why. I am going to try burning the tech bench windows 10 iso file onto a dvd and see if I have more success. If that doesn't work I will move to the mediacreation tool. Please let me know if you have any other thoughts. As I said before, the instructions for creating an installation USB stick included in the techbench zip file were confusing to me. Its possible I did not even prepare the USB right.

samhandwich22 said:

The BIOS isn't picking up the USB drive, "no boot device" detected. I am not sure why. I am going to try burning the tech bench windows 10 iso file onto a dvd and see if I have more success. If that doesn't work I will move to the mediacreation tool. Please let me know if you have any other thoughts. As I said before, the instructions for creating an installation USB stick included in the techbench zip file were confusing to me. Its possible I did not even prepare the USB right.

The media creation tool will create the USB for you - under the option of make media for another PC.

Thank you! It was successful! In retrospect this appears to be a simple solution but it had me worried because it failed to read the license key in my Bios when I attempted it before. Using Windows 10 Iso from the mediacreation tool seemed to do the job when the previous Iso I tried with did not.

samhandwich22 said:

Using Windows 10 Iso from the mediacreation tool seemed to do the job when the previous Iso I tried with did not.

If you had the first version of Windows 10 ISO (build 10240), it did not have the capability to use a Windows 8 product key.

That explains it. Thanks again! That was so easy really!