Does upgrade require proof of prior version?

I have several family PCs that I will be upgrading to Windows 7. Some ar XP and one is Vista. I want to do a clean install on all by wiping the partition and then installing Windows 7. Two questions:

1. Will I need to provide the XP and Vista install disks for the install to work?

2. Should I launch the install from within each OS and wipe the partition from within the install or should I wipe it first then boot the install?

Thanks!!

Don't forget to BACK UP all of your important data on your XP machines BEFORE you do the install.
(I figure you know what you are doing with a clean install, but this reminder is for any other people who are reading this forum)

If you purchased an upgrade disc, then you will need to follow the upgrade instructions.

The upgrade discs look for the presence of the prior OS to go in as intended. No, you don't provide the prior discs.

If you want to format or anything like that, do it from within the installation itself. If you boot from the upgrade discs you should be able to do partitioning during installation too.

If you wipe the drives on your own first, you're going to start to run into issues with the "upgrade" discs.

Many users are having their key rejected for the following reason.

If you have purchased an 'Upgrade' you MUST run setup from within Vista or XP.

You purchased an upgrade so you must have something to upgrade from.

Trying to boot to a virgin drive with no memory of a previous OS will not work.

Yes there are hacks but its only been 3 days and we don't know how MS will handle installs that are not legal.

This was the oddest "upgrade" installation I have ever done actually. I first stuck the 7 disk in while in Vista and selected custon install thinking it would do a clean install and it didn't it upgraded but non eof my programs were there so not sure happened there. Second time I booted to 7 disk and did a format of the drive and did a clean install....it never asked for any prior Windows media to verify qualification for an upgrade. It just installed and that was all there was to it.

In the past I have had to at least show my prior OS disk for a clean install but not this time. The box also says that the Professional version upgrades ALL version of Vista and XP so that must have changed from the original thoughts. I had Vista Ultimate and it upraded to 7 Pro without any issues. It was almost like this wasn't an upgrade disk at all and the full version.