I remember one of the most useful pieces of info anyone ever gave me regarding XP and my current build, they said buy the upgrade only, IF you still have your 98 disk. Because the entire OS, was on the XP update CD, and during installation if XP didn't find a Windows OS on the HD, it would ask you to insert you qualifying product (Win 98, Win 95) disk. Then Badda bing, it asked you to insert your XP disk, and the installation went to completion. My question is, does it work the same way with Vista?

Signed
Vista Ignoramus

this might interest you...

http://www.microsoft.com/windows/win...e-advisor.aspx

You may want to check this out as well.

Well done, that's exactly what I was looking for

Zalax

If you're upgrading a current system you can use the upgrade, but if you're building from scratch you can buy an OEM copy, they're usually cheaper than Upgrades (I believe) and are great if you know what you're doing. The one downside is that they don't include the same microsoft support that Retail (and I'm assuming Upgrade) does since you're supposed to be the system "manufacturer".

On vista upgrade you need to install it from within a working windows OS. It no longer accepts a CD as valid proof.