Here in Germany it is not allowed to bind a License to a specific hardware.
That was ruled years ago.
You can read about it here:
https://www.software-express.de/hersteller/microsoft/oem/
So, Yes I can change the Motherboard and still use the same License.
Thats also why you can still buy these Licenses online.
So the Question remains:
How do I activate the WinXP.
With the original Code or different Code, we have few to choose from.
Microsoft should offer a Solution since they sold the Software, but they are not.
If they shut down their WinXp-Activation-Servers and Phone-Lines, they should offer a Solution
for the few Customers who are unable to use newer Version of Windows with certain Apps.
If you ask Microsoft-Customer-Service they seem to know nothing about this matter.
So there is no official statement except to upgrade to newer Version.
Microsoft simply refuces to accept the Fact that some Apps won't work on newer Windows,
which makes me wonder, because it seems it was made that way on purpose.