I am wondering how this works. I'll tell you the story of my computers:
I have one laptop and one desktop. One laptop was running Windows 7 Home Premium (32 bit) and my desktop is running Windows 7 Ultimate 64 bit. Now, I have already upgraded my laptop to Windows 8 Pro and it installed a 32 bit version! I suppose because the installer detected that the previous version was 32 bit. I installed Windows by downloading the ISO and burning it on a DVD.
Now, I want to upgrade my desktop as well! I have already bought the key for Windows 8 (via PayPal using the Upgrade Assistent) but I do not want to waste another DVD if it has the same contents. So, can I use the DVD I used to install Windows in my laptop for my desktop, even though my desktop has a 64 bit OS (and I want it to install a 64 bit Windows 8 as well)?
In other words: the ISO that I downloaded, does it contain the 32 bit and the 64 bit installer? Or does the Upgrade Assistent download the correct (i.e. 32 bit or 64 bit) installer?