Mary said:
Why do you say that? Anyone with a valid XP license and the xp cd's for
proof
of purchase can buy the Upgrade version and do a clean install.
Sorry, this information is not correct.
Upgrading from XP x86 to Vista x86 using the upgrade version, your only
option is to start setup within a genuine XP installation, no advanced
options available, no ability to do a clean install.
Upgrading from Windows 2000 to Vista x86 using the upgrade version, you do
have to start setup from within W2K, but in this scenario your only option
is to do a custom install.
If you are upgrading anything to Vista x64 upgrade version, then you can
start the upgrade by booting from the Vista DVD where you can do a clean
install. During this setup process it will check the hard drive for a
qualifying OS for the upgrade.
See
http://www.microsoft.com/windowsvista/getready/upgradeinfo.mspx for
other info.