Tyler Too writes "With six different versions of Vista due once it ships, figuring out an upgrade path can be confusing. Microsoft has tried to clear things up with a 4x6 matrix laying out your options. 'In short, users of XP Home can do an upgrade install to any of the four Vista versions. However, XP Pro users can only perform upgrade installs to Business or Ultimate.' And if you're not running a 32-bit version Windows XP, there's no upgrade path for you at all."