Versions of the new OS occupied the top three spots on Amazon's software "Bestsellers" listing as of Friday.
Windows 7 Home Premium Upgrade, Family pack, held the top spot. Home Premium Upgrade was second, and Windows 7 Ultimate Upgrade was third. It was a clean sweep for Microsoft in Amazon's top five, as Microsoft Office 2007, Home and Student edition, was fourth while Windows 7 Professional Upgrade took fifth.
Though not scientific, the listing is generally seen as a good indication of a product's popularity, given the large volumes of transactions that occur on Amazon.
Microsoft formally introduced Windows 7 Thursday at a launch event in New York City. Speaking at the event, CEO Steve Ballmer called the OS more responsive and "less busy" than its predecessor, the widely maligned Windows Vista.
Microsoft needs the product to be a hit, as Windows sales have slumped badly of late.
Microsoft said Friday that Windows sales for its fiscal first-quarter were off 39% year-over-year, though much of the decline was due to the company's deferred recognition of $1.5 billion in revenue during the quarter to account for a program that let consumers who purchased a Vista PC during the weeks leading up to Windows 7's launch to upgrade virtually for free.
The full version of Windows 7 Professional is $299, with upgrades going for $199. Windows 7 Ultimate is priced at $319, with the upgrade version at $219. The full version of Windows 7 Home Premium is priced at $199, with an upgrade from Vista or XP costing $119.