Activation with old key?

There are three product keys that Showkey will show.

1. The currently installed product key. If your Windows 10 is an upgrade from a Windows 7/8/8.1, then the currently installed product key will be a generic product key that is the same for all Windows 10 upgrades, depending on version. The two most common are:
TX9XD-98N7V-6WMQ6-BX7FG-H8Q99 for Windows 10 Home and
VK7JG-NPHTM-C97JM-9MPGT-3V66T for Windows 10 Pro.

Once an upgrade from a previous Windows 7/8/8.1 has been completed and activated successfully, these product keys can be used to both install and activate Windows 10 because Windows 10 will retrieve the digital entitlement to activate from Microsoft activation servers that was saved there during the upgrade. If you have not upgraded previously, then these product keys will install Windows 10 but will not activate it.

If you purchased Windows 10 from a retailer, you will get a unique product key which you will have to enter to install and activate Windows and this will be the product key retrieved by Showkey as the current product key.

If you purchased a computer with Windows 10 pre-installed, the current product key will be the key provided for the Windows 10 installation that is stored in bios.

2. If you upgraded from Windows 7/8/8.1 to Windows 10 and have not performed a clean install, then Showkey will show you the key of the Windows 7/8/8.1 that was installed at the time the Windows 10 upgrade occurred. You may or may not be able to use that product to install and activate the Windows 7/8/8.1 that was on the computer because it is possible for that product key to be one assigned to a computer manufacturer used to install and activate the factory loaded software and it won't work for a vanilla clean install of Windows 7/8/8.1. It might also be different that the sticker on the computer because the manufacturer must provide you with a product key that you can use to install Windows 7/8/8.1 with - and you can't use the product key that was assigned to them as a manufacturer. Once you do a clean install of Windows, this product key will go away because the clean install of Windows will overwrite it.

3. Showkey will show you any product keys stored in bios. Again, this may or may not be a product key that you can use to install and activate vanilla Windows. This may also be a key that can only be used with the factory software load.

Showkey WILL show you the product keys that were used to install and activate the Windows that was on the computer at the time that product key was used. It won't present random keys. You might not be able to use the product key shown to activate Windows because of the various reasons described above.

Thanks, that clarifies a lot! So my situation must be that when I installed w8.1 retail the first time it was on a used motherboard, and for that reason it won't show me the vanilla key I used to install it, at least not after w10 update. Had it been a new mobo things would probably have been different I suppose.

So it's just best to hold on to the original key. I now successfully used it to install on a brand new build without problems, the sticker one I mean, not the one show key shows.