Able to get free Windows 10 upgrade ISO without knowing product #

[criel]

Hi all

I am working on upgrading my PC and getting a new hard drive with it as well. Starting from scratch, so I'm not sure if I will be able to download the ISO to install windows from a usb drive without having to buy a new copy? When downloading the iSO so they ask for the existing product key for my current windows?

How big is the ISO file so I know how big of a usb to get?

 

[Math Geek]

if doing a fresh install without doing the upgrade first then you will need the product key to input. otherwise how will windows know you qualify for the upgrade? if you have a copy of win 7 running now, then simply get your key from that install so you have it for later. plenty of programs out there to get at it. magic jelly bean is popular one as are a hundred others.

and an 8 gb usb drive is enough for the install but 16 gb will give plenty of cushion in case you want to have other things on the drive as well.