Windows 7 upgrade question

I’m running windows 7 RC1 on both my machines at home. I’d like to purchase and upgrade version, which is much cheaper even than the OEM version. I have full retail versions of vista for each PC, my question is: When I use an upgrade copy of windows 7, do I need just the valid vista serial #, or do I have to physically install vista on the machines first in order to upgrade? 'cause if I have to install vista first then I won’t bother.

I was able to do a clean install using the upgrade disk. When it prompts you to, do a custom install and then DO NOT enter the serial.

After the install is complete, activate it and it will then ask you for the serial.

I did this on a clean partition which allowed me to keep the windows XP as a bootable back up (see also dual booting).

The article has a few methods about doing a fresh install, but the first worked for me.

I did not need to enter a Vista or XP serial and this was with the Win 7 Home Premium upgrade that they presold for $50 a few months ago.

Both and sell OEM copies cheaper than the upgrade version.

The OP might be getting the student deal, which is an upgrade to Home Premium or Professional for $30.

Basically, if you already have Windows installed and you install the upgrade it should activate no problem, even if you do a “clean” install that deletes your old partitions.