Users can do a "clean" installation of Windows 7 using an upgrade license to save $80-$100 over the price of a "full" edition, a popular blog reported today.

According to Paul Thurrott, who writes the Supersite for Windows blog, Microsoft's upgrade media and product keys can be used to do a full installation of Windows 7 on PCs that do not have an earlier version of the OS.

Microsoft's Windows 7 upgrades are designed to do "in-place" or "custom" installs on PCs running Windows XP, Windows Vista or one of the preview editions of Windows 7. But Thurrott said that a few simple steps lets users install upgrade editions, which are considerably cheaper than the full versions designed for fresh installations.

Windows 7 Home Premium, for example, costs $119.99 as an upgrade, but $199.99 for the full edition, a difference of $80. The full versions of Windows 7 Professional and Windows 7 Ultimate, however, cost $100 more than the corresponding upgrades.

Nearly three years ago, Thurrott showed users a similar trick with the then just-released Vista; that technique, however, required users to install Vista twice.

Full story: Computerworld