Windows 10: 3 PC's: Free upgrade using ISO?

You must keep your data and programs for the upgrade to activate. Once you get an activated upgrade on that computer you can then clean install, on that computer.

 

Yes, 7 Ult x64 and 8.1 Pro x64 installs could be updated using the same Win 10 Pro x64 ISO. I would use the keep files and applications option just to be sure you upgrade and activate with 10 free and clear.

 

That's OK. I don't mind doing the "dirty" upgrade first, just as long as I can use the same ISO for the initial upgrade and later for the clean install.
Thanks to all who answered.

 

Links to Microsoft documentation? Good luck with that.

I upgraded both my desktops using an .iso downloaded using the Media Creation Tool. As they were Windows 8.1 machines, I was able to mount the .iso directly and run the upgrade from the virtual DVD. (Win 7 has no built in means of mounting an .iso, so you'd need to install a freeware utility to do that, extract the .iso with a utility like 7Zip, or make installation media. If you make an installation device, DO NOT boot from it to run the upgrade. Run from your old Window OS.) I believe that you can also get the .isos from here:

[Tech Bench

I know from personal experience that if you wish to upgrade a qualified OS with the free upgrade, the versions must match (home to home, pro to pro). It's a bit more detailed than that:

Microsoft has announced the upgrade matrix for Windows 10

From MCT, you can specify an installer that can update both 32 and 64 bit versions. That won't fit on a single-layer DVD. And, you don't need it.

I don't know, but I assume that since separate downloads are available for the N versions, they are necessary. (I don't know if you can install a non-N upgrade over an N OS that had the separate Media Pack - or whatever it's called- installed to bring it up to the US version.)

There's no mention of 8.1 with Bing in the upgrade matrix. (Perhaps because, if memory serves, it was not for sale in the US.) I think it's equivalent to 7 Starter, and it may upgrade to 10 Home.

I suggest getting the Pro N X64 for the Ult N and Pro N machines. I'm not sure which .iso you'd need for 8.1 with Bing, but it'd be Home N X64 or Home X64. (I'm betting on the N.)

 

According to this:
How to Determine Your Free Windows 10 Upgrade Version

Windows with Bing gets Windows 10 Home. Don't know if it is the N version or not.

 

Do the UPGRADE first and then the CLEAN INSTALL.
(Make sure the UPGRADE is activated.)

The same CD/USB will work for both.
(Check 'format this drive' on the CLEAN INSTALL only.
Don't bother with the activation number for either process.)