I cant make head or tail of what can be clean installed, whether XP has to be installed before a full upgrade, whether OEM's can have any hardware changes or whether downloaded upgrades (e.g. Premium to Ultimate) adopt the same licence as the original install.Take a look at this blog here, particularly the last few posts:http://windowsvistablog.com/blogs/windowsv...ents-today.aspxNot sure that MS know either!

The link refers to the upgrade path between various flavours of Vista, so you can upgrade to a more sophisticated version at even more expense, but with a discount. Lucky us. It would be ludicrous if doing so exposed the user to the installation limitation of an individual licence. But given we are talking MS, nothing would surprise me!Allcott

It is clear as mud. Can I use an x86 vista upgrade license in the following:I have Win XP x86 on drive C. I want to boot Vista DVD, wipe and reformat C, and install vista.How about the following modification. I have win XP copy 1 on C, and win XP copy 2 as dual boot on D. I want to run Vista either from DVD or from Win XP copy 1, wipe win XP copy 2 and reformat and install vista on D.Or do I have to buy a full on Vista to do this?Also, is it possible to run any flavor of Vista in a Win XP VM?scott s..

Hi Scott,It's not only unclear but various sources are coming up with different answers.The most likely method which seems to work is:1. Boot with the Vista-DVD.2. Don't enter your key when asked for it.3. Delete the partion where Windows currently resides.4. Allow the OS to install but don't attempt to activate it. It will error out anyway.5. Run setup from the DVD in the new Vista installation and delete the Vista partition.6. During this second install, you can enter your key. You can also activate it when finished.It's a lot of work but the upgrade does save you money and this method gives a true clean install whereby the drive is formatted prior to the installation.Here is a post that outlines the procedure: http://www.hardforum.com/showthread.php?t=1151184Regards,Jim Karn