RayLopez99 wrote:

Then I must find a key within 30 days to 'activate', agree?

You have had an *activated* copy of Windows 10
on the machine already. Correct ?

If so, there is nothing to buy. The installation process
will contact the Microsoft license server, the license
server will say "I've seen that machine before, here is
your token". And the job of activation is automatically done.

There is nothing to buy!!!

You've downloaded media. Use it.

*******

There's probably nothing wrong with that copy
of Win10 on the drive already. It'll be some little
problem. I had to fix one of these "little problems"
two days ago. It's annoying but it can be fixed.

Paul