What happens during a Windows 2000 Upgrade to Vista?

I read that you have to do a clean install in order to upgrade to vista, but
the upgrade version cant do clean install unless you use that install twice
trick. So what exactly happens for a Windows 2000 upgrade to vista?

You start from inside of Windows 2000. You tell it to do a custom install
and to do a clean install from there.

It then moves all of the old Windows files to a Windows.old directory which
you can delete afterwards and clears everything else off.

So it basically is a clean install in a true sense, but the drive just
wasn't formatted beforehand.

"Emory Tech" <EmoryTech@discussions.microsoft.com> wrote in message
news:1F2ECF93-C464-4A62-B02E-69FF6C0775B6@microsoft.com...
>I read that you have to do a clean install in order to upgrade to vista,
>but
> the upgrade version cant do clean install unless you use that install
> twice
> trick. So what exactly happens for a Windows 2000 upgrade to vista?

In article <1F2ECF93-C464-4A62-B02E-69FF6C0775B6@microsoft.com>,
EmoryTech@discussions.microsoft.com says...
> I read that you have to do a clean install in order to upgrade to vista, but
> the upgrade version cant do clean install unless you use that install twice
> trick. So what exactly happens for a Windows 2000 upgrade to vista?
>
This is what happened in my situation with Windows 2000 installed on
the first partition and a second newly formatted partition for Vista.

Booted directly from an OEM upgrade Vista Home Premium DVD the same as
I did with the Vista Beta 2/RC1/RC2 DVDs. Selected a custom install and
pointed to the new partition for Vista.

Vista installed and the original Windows 2000 partition was not
changed. Windows 2000 shows up in the Vista boot menu as previous
version of Windows (or something like that).

Warren