I assumed if I wanted a hard copy of Windows 10 that I could shove in my drive and do a clean install if I ever needed to do so, I would have to pay over my hard-earned cash in a computer shop.
However my mate told me yesterday that because Windows 10 was a free upgrade I can just download an ISO 10, burn to a disc or thumb drive, and use my old W8 install code. Can anyone please verify whether this is in fact the case or not?
Mostly, yes. Once you have successfully performed an upgrade install, you can then clean install from a DVD created by the Media Creation Tool which you can download from Microsoft.
You cannot (yet) use your old key to activate, you must activate on the same machine you upgraded from and activation will be automatic.
There is rumor that Microsoft is going to allow you to use your old code to upgrade in a future version, but we don't know if that will be the case yet.
From my understanding you can use your old key with version 1511 build 10586.
Did you say "Activation will be automatic"? I assume this is due to some fancy chip on the motherboard that registers the Pc with Microsoft when you first install it.
What if I also change my hardware substantially?
No. When you upgrade, MS calculates a hardware hash and stores it with your activation certificate. When you reinstall later, the hardware hash is recalculated and looked up on MS's activation servers.
I have not actually seen this or heard it was actually implemented in this version. Maybe i'm wrong.
It was implemented and I've done it on two computers that had not had Win 10 installed or activated previously. I used a Win 7 key on one and a Win 8.1 key on the other. Both installed and activated with no problem.
I remember now, I was referring to the TPM (Trusted Platform Module) chip on all Windows compatible hardware these days.
The TPM is only used for encryption purposes. It's not use for activation.
The new build 10586 will also read and use Windows 8/8.1 OEM embedded keys. I did a clean install on my laptop to a blank hard drive and 10 Home was installed with no prompt for a key and no prompt to chose edition. Activated with a digital entitlement too. showkey shows the installed key as the generic 10 Home key. 10 Home was never installed on this PC before this. It was previously running 10 Pro with a digital entitlement, an upgrade from 8.1 Pro, before I wiped the drive. To get back to 10 Pro I did a change key and entered the 10 Pro generic key. It upgraded and activated OK. Just a heads up. I have added a PID.txt file with the Pro key to stop it from happening again and clean install Pro instead of Home next time around. My laptop has a Windows 8.0 Core OEM embedded key. If your doing a clean install you may want to double check what version gets installed. You may be surprised like I was.