Checking my W10 Product Key, MS Toolkit gives me one key, and the software program, Produkey gives me a different one. How can this be?

Because they are just placeholders it's done on a hardware id when you upgraded.Stored on M$ servers the only time you need a key is when it is clean installed on a machine that never had it installed before.You can install without a key and phone them to activate if you change motherboards for example but be prepared to spend some time on the phone mine took over an hour.

Thanx. I haven't called yet. Do you have a #? I have 2. They are
888-571-2048 and 888-352-7140.

The activation screen will give you the # in your area and you will need to have that up when you call.It'll be self explanatory as you try to activate.