[anotherblue]

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.

[SquareWheel]

I see, thanks for clarifying.