You can install the MS upgrades on a blank hdd too, can't you? It's been some years but I thought they just used to ask for a disk from the "qualifying upgrade" product to be inserted during install.

The parent was specifically replying to

> you can only install it on Macs (which already have OS X installed).

It wasn't an attempt to compare OS X and Windows installations.

Usually, you can do following:

- Install Windows retail SKU, but do not activate it. You can borrow disk or download ISO for this. - Start installing upgrade version, then reformat partition, supplying upgrade key in the process.

At the end, you will have Windows upgrade installed and activated, fully functional.

Wait, you install the old Windows version, then the upgrade, and then reformat? That doesn't sound right to me...

No. If you have any Windows installed on the machine, then you just start upgrade process from it, then after EULA screen, you choose Custom Installation and then reformat the disk and continue with installation.

For Windows 7, if you have machine with empty disk, then you start installation of upgrade version, but do not provide product key and uncheck 'Activate' checkbox. This will install Windows in trial mode. Then, start upgrade setup again and let it 'upgrade' OS... After that, you have activated Windows on the machine.

For Windows 8, I am not sure if process of double installation will work.

I see, thanks for clarifying.

Not with the latest versions of OSX. Lion...maybe. I think you can USB it. As far as I have read Mountain Lion is download only.

Exactly, you download it and then burn the disk image to a DVD or whatever media you'd like to boot from.

You can do that with Windows 7 upgrade disks too, albeit with a small bit of hackery.

True, that is an advantage! I was just speaking in licensing terms.