Recently we discussed about upgrading to Windows 7 from previous Windows versions. Microsoft has released the supported upgrade paths from previous Windows versions to Windows 7 which will be described here. It is also to be noted that the upgrade from Windows 7 RC to Windows 7 RTM is NOT supported. Microsoft has released the supported and unsupported upgrade paths to ease the switching from previous Windows versions to Windows 7. For example, Windows Vista (SP1, SP2) Business will be able to upgrade to Windows 7 Professional, Enterprise, Ultimate; Enterprise to Enterprise; Home Basic to Home Basic, Home Premium, Ultimate; Home Premium to Home Premium, Ultimate; Ultimate to Ultimate.

In addition, Windows 7 to Windows 7 upgrades are also supported through normal upgrade and ‘Anytime Upgrade’ option available within Windows 7. However there are few key areas where the upgrade is not supported. They are:

1) Upgrade to Windows 7 from any of these OSes is NOT supported: Windows 9x, Windows Me, Windows XP, Windows Vista RTM, Windows Vista Starter, Windows 7 (Milestone-3), Windows 7 Beta, Windows 7 RC, Windows 7 RTM and Windows 7 IDS.

2) Cross-architecture upgrades like x86 (32-bit) to x64 (64-bit) is not supported.

3) Cross-language upgrade is not supported.

4) Cross SKU upgrades like Windows 7 N to Windows 7 K are not supported.

5) Pre-release upgrades across Milestones like Windows RC to Windows RTM is not supported.

Refer the official .doc file issued by Microsoft regarding upgrade paths here.

In addition to the above information, I would like to add that, Microsoft offers free upgrade to Windows 7 if you purchase a Windows Vista (OEM) installed PC between June 26, 2009 and October 22, 2009.

In case you want to know whether or not your PC is capable to run Windows 7, you can download the Windows 7 Upgrade Advisor and evaluate yourself.

Source: Microsoft.