Microsoft is excited about Windows 8. So much so, in fact, that the Redmond software giant wants to make sure that everyone can upgrade straight to its latest and greatest achievement, even from operating systems as old as Windows XP. In other words, if you’re running any version of Windows XP, Windows Vista, or Windows 7, you will be eligible for an upgrade to Windows 8.

The upgrade path for each version of Windows might seem complicated on the surface, but it’s actually fairly simple. Essentially, any version of Windows XP, Vista, or 7 will be able to upgrade to an equivalent or better version of Windows 8, provided that it’s based on the same architecture (32-bit or 64-bit). It’s also important to point out the rather obvious fact that Windows RT will not be sold as a standalone OS, so there is no way to upgrade – let alone purchase – the ARM-based version of Windows 8.

Here’s the breakdown of supported upgrades:

Windows 8: Windows 7 Starter, Windows 7 Home Basic, Windows 7 Home Premium, Windows Vista, and Windows XP

Windows 8 Pro: All of the versions supported by Windows 8, plus Windows 7 Professional and Windows 7 Ultimate.

Windows 8 Enterprise: All of the versions supported by Windows 8 and Windows 8 Pro, plus Windows 7 Enterprise.

In most cases, personal data, system settings, and applications will be preserved through the upgrade. There are, however, a few exceptions to this rule. Those coming from Windows Vista or Windows XP – or upgrading from a different language – won’t be allowed to keep system settings or applications (although personal data will be preserved), while those on Windows Vista SP1 will only lose their applications.

At this point, it’s unclear whether all versions of Windows XP and Vista will be allowed to upgrade to the baseline version of Windows 8, or if some will be forced to go to a more expensive SKU like Pro or Enterprise. Exact pricing, too, remains a mystery. Microsoft has promised to offer $14.99 upgrades to Windows 8 Pro for anyone who purchases a new Windows 7 PC between June 2, 2012 and January 31, 2013, but those with older computers will have to acquire an upgrade copy of Windows 8 at full price.

[All About Microsoft]