Hi Kelvin
My name is Andre Da Costa; an Independent Consultant, Windows Insider MVP and Windows & Devices for IT MVP. I'm here to help you with your problem.
Whoever installed it, might have installed a volume license (organization key) on your computer.
Windows 10 Pro/Enterprise volume license clients are used by large organizations that deploy Windows 10 in bulk to hundreds or thousands of computers. Sometimes, users will copy these organization keys off the Internet and use them to install Windows 10 Pro/Enterprise, but they are blocked from activating because it can't reach appropriate KMS host (Server computer) which handles the activation request.
You would need to purchase a genuine license for Windows 10 Pro from the Microsoft Store. If you can't afford Pro, you can purchase Home, make a bootable copy then perform a custom install.
http://www.microsoftstore.com/store/msusa/en_US...
If you choose to purchase Windows 10 Pro key, you will receive it by email and you can enter it.
Click Start > Settings > Update & security > Activation > Change the product key then enter the new product key then click Next to Activate
If you purchase Windows 10 Home, you have a couple options:
Option 1:
Click Start, type: CMD
Right click CMD
Click Run as administrator
Type:
slmgr /ipk <ProductKey>
(Replace <ProductKey> with one of these below)
YTMG3-N6DKC-DKB77-7M9GH-8HVX7
Exit the Command prompt then restart.
There is another way you might be able to downgrqade to Home without having to reinstall everything, but its pretty advanced.
Open Registry Editor (WIN + R, type regedit, hit Enter)
Browse to key HKEY_Local Machine > Software > Microsoft > Windows NT > CurrentVersion
Change EditionID to Core (double click EditionID, change value, click OK). In your case it should at the moment show Pro
Change ProductName to Windows 10 Core. In your case it should at the moment show Windows 10 Professional
Browse to key HKEY_Local Machine > Software > Wow6432Node > Microsoft > Windows NT > CurrentVersion, change the same two values as in steps 3 and 4 above
Close the Registry Editor
Download and launch the Media Creation Tool, do an in-place upgrade by launching the setup from desktop (not booting with Windows 10 Home install media)
When asked, enter your valid Windows 10 Home product key then select what to keep (settings, personal files and apps, only personal files or nothing)
Windows 10 Home in-place upgrade will be done now.
Download the Media Creation Tool Now
http://go.microsoft.com/fwlink/?LinkId=691209
Right click the MediaCreationTool.exe file then click Run as administrator.
Accept the End User License Agreement:
Select the option Upgrade this PC now if you want to upgrade right away,
Click Next
Accept the End User License Agreement.
Wait while Windows 10 setup does one final check to ensure your system is ready.
Windows 10 setup will check if you have enough disk space.
Please note, you have the option of choosing what you would like to keep, which includes personal files, apps and settings.
If you want to perform a new install or just keep your files click Change what to keep. Once you have chosen the desired options, click Install to begin.
This will be your screen for a little while. During the installation, your computer will restart several times.
After the first restart, Windows 10 setup will resume. You will notice the setup experience has once again been refined from the previous animated circle. This will be your screen for a while. When complete, Windows 10 setup will restart automatically.
Sign into your account.
Wait while Windows 10 completes application updates and post setup tasks.
ThatÕs it, the Windows 10 Creators Update is installed.You can check Windows Update for latest updates, click Start > Settings > Update & security > Windows Update > Check for Updates.
If you are finding it difficult to carry out some of the steps described below, please review detailed instructions how to perform them:
https://www.groovypost.com/howto/prepare-comput...
Option 2: Perform a Custom install:
How to: Perform a Custom install of Windows 10
http://answers.microsoft.com/en-us/insider/wiki...
how to recover your files from Windows.old:
https://answers.microsoft.com/en-us/windows/for...