Hello, John. I'm Greg, here to help you with this.
I believe you're referring to the Independent Advisor's post here:
https://answers.microsoft.com/en-us/windows/for...
Is this correct?
Do you have the same problem as the customer in that thread? Please fully explain your issue so I know what to suggest, since the registry edit you're asking above may not be advisable.
How was Windows 10 originally Activated on the PC? Did it come preinstalled from Factory, was it Upgraded with free or paid Upgrade, or was it a retail copy and license?
For Upgrade when you first upgraded and it activated it assigned a permanent Digital License to the PC in Microsoft Activation Servers so you can reinstall any time and in any way you want as long as you reinstall the licensed version. It should reactivate soon after going online.
Factory installs have the Product Key embedded in BIOS or UEFI firmware and should activate themselves, but you can check for the key by installing ProducKey and look for OEM-BIOS key: http://www.nirsoft.net/utils/produkey-x64.zip then insert it in Settings > Update & Security > Activation > Change Product Key.
Retail keys must be reinserted during install or in afterward in Settings.
Which one of these describes how your Windows is activated?