I plan on upgrading to Windows 7 64 from XP 64 this October but I am a little confused as to how the pricing for this works. I understand that XP users are eligible for the upgrade price for Windows 7 but a few things about this does not make sense to me. The first thing is where to purchase Windows 7 for the upgrade price. I looked on Amazon and they have a SKU for Windows 7 Upgrade (Amazon.com: Microsoft Windows 7 Professional Upgrade: Software) but does this apply to XP users or just Vista users? As in, if I buy that SKU, then come October, I can use that CD Amazon ships to me to do a clean install of Windows 7 on my XP machine? Also, would I have to prove to Amazon in some form that I currently own XP as opposed to Vista at the time of purchase? The second thing that confuses me is that Amazon also has regular Windows 7 SKUs for full price (Amazon.com: Microsoft Windows 7 Professional: Software). Now assuming that you can purchase the Windows 7 Upgrade SKU and do a clean install on your XP machine, what is the point in buying the OS at full price? Could someone please break down the XP upgrade path to me?