Windows Vista users can follow multiple upgrade paths to Windows 7. As was the case when upgrading from XP to Vista, you will only need to perform a clean install if you are going to a version that is lower on the food chain. For example, if you are going from Windows Vista Ultimate to Windows 7 Home Premium, you would do a clean install. If you are going from Windows Vista Home Premium to Windows 7 Ultimate, you do not need to do a clean install. When you switch to a higher version, you're adding on the existing functionality, but when you're going to a lesser version, you're taking away functionality, thus the need for a clean install.

Clean installs will also have to be performed when upgrading from a 32-bit version to a 64-bit version, regardless of edition. Unless the user chooses to repartition or format the current partition, Vista's files from C:\WINDOWS will be preserved under C:\WINDOWS.OLD, just as when upgrading from Windows XP to Windows Vista.

As with Vista, each DVD includes the various editions. Unlike Vista, every edition of Windows 7 is a superset of the previous edition, so you will not lose any features when upgrading. Once you have some edition of Windows 7 on your system, whether you purchased it via an OEM or just upgraded from Windows XP or Windows Vista, you will be able to upgrade to a "more premium" version of Windows 7 by purchasing an upgrade key to unlock additional features, just as with Vista. This is called Windows Anytime Upgrade (WAU). For example, you could start off with Windows Vista Home Premium, upgrade to Windows 7 Home Premium, and then later choose to upgrade to Windows 7 Professional.