Hi Pat566,
I'm Christine, a Windows user like you. Looks like you would like to upgrade from Windows 10 Home to Pro. No worries, I'll help you. :)
What is the error message that you're getting?
May I know where did you purchase your Pro Key? (please do not send it here for your privacy and security)
Please try to press Windows key + R and type slui 3 then hit enter
Kindly type your Pro key there and check if it will upgrade to Pro.
The usual way to upgrade to Pro from Home is going to activation page, and look for Go to Store under "Upgrade your edition of Windows".
And follow the prompt.
Please check the reference below:
Upgrade Windows Home to Windows Pro
https://support.microsoft.com/en-us/windows/upg...
Please let me know the result. I'll be happy to assist you all the way until it's resolved.
Thank you,
Christine L
Independent Advisor