This is going to confuse a lot of people that aren't familiar with 'root'
accounts.

Basically, the first user set up in Vista is the default Admin (or root)
user.  This is the user who will have full control over the system and when
another user is running as a standard user, it will ask for this users
password to perform administrative tasks.

XP Home never asked you to set up an Admin user during setup, only during
first run after install and it never prompted you to set a password.  This
is one of its greatest security flaws.

I think Microsoft is going to get a lot of tech support calls when the
screen to set up the Admin account during the installation appears.  Many
will believe they need a user name and password to continue and won't
understand that they are setting up a user name and password, even though
it's clearly explained on the screen itself.

Mic