I've just noticed that at some point going to 8 or 8.1 I was upgraded to Pro not Home.

Would this be why the extracted key wasn't valid? (I was using a Win 10 Home USB ISO).

Currently using...

I realise I need to clean install to go 32>64

What I'm asking is whether I cam extract the product key from a 32 bit install then clean install 64 bit with that key.

The machine is currently...

Hi all, this is my first post here

I've updated 2 machines from 7 64 bit and 8.1 64 bit to Windows 10 64 bit ok.

However... I have a Dell Inspiron 530 from 2007 which originally came with Vista...