Upgraded my first WIn 7 to Win 10. 
 
I was under the impression that I would be given:
 
1. A Cereal Number
2. A way to get an ISO image of the Win 10 installer
 
Nada so far (been over 24 hours)

Serial is not needed, it tied it to your hardware. There are no transfer rights (like a retail copy would have) so no need. When you do a reinstall it should just activate without bothering you.
 
This thing right here will get you an ISO.

If the number was bios based it is used but changed sorta, so they say,...
 
I haven't looked to find the one for the comp with the embedded number.
 
And, you needed to use the install assistant and download the ISO file before install.
 
 
More insanity about bad drivers being downloaded automatically:
http://www.forbes.com/sites/gordonkelly/2015/08/08/windows-10-forced-updates-causing-endless-crash-loop/
 
Beware.  There are fixes for pro but not so easy for home,....
 

YouDontHasToCallMeJohnson
If the number was bios based it is used but changed sorta, so they say,...
 
I haven't looked to find the one for the comp with the embedded number.
 
And, you needed to use the install assistant and download the ISO file before install.
 
 
More insanity about bad drivers being downloaded automatically:
http://www.forbes.com/sites/gordonkelly/2015/08/08/windows-10-forced-updates-causing-endless-crash-loop/
 
Beware.  There are fixes for pro but not so easy for home,....
 

I only have one Home version and it's got a Acronis backup JIC.

Cerial number is on the system page along with the frosties and cooko pops.
Copy and paste that (just in case) although I found it useless.
Download the ISO haven't got a link sorry google.
I've been upgrading then wiping with clean install with a format.

Here is the page to create a windows 10 ISO:
https://www.microsoft.com/en-us/software-download/windows10ISO
 

I did a D/L of the x64 installer and put it on a USB key. Works great, at least the 3 times I've used it.

MS is using a server based system linked to your computer identity hash. That is why you need to do an upgrade installation to get your new Win10 system registered, then when your machine is registered you can do a clean install from the iso and when it checks to see if it is in their database it will fine a legal machine registration and activate. That also probably means that your free upgrade is not going to be capable of activation on a new machine.
 
http://www.zdnet.com/arti...39&ftag=TRE17cfd61

slartabartfast
That also probably means that your free upgrade is not going to be capable of activation on a new machine.

And the tag on question to that is:
 
What if I have to (further down the road) replace either my hard drive or mobo? Is it the same machine? I would venture to say it's not if the mobo is changed but maybe it's still the same if it's a new hard drive.
 
update: just read the article. Looks like the license is "mainly" tied to the motherboard and not hard drives or video cards. Seems like a new mobo only requires a phone call to MS to get reactivated.

Bapu, you are full of interesting finds. I never would have sought this info, but I'm thankful for it.