In preparation for the migration from Windows 8.1 to 10, Microsoft has revealed that it's no longer selling Windows 8 and or computers that have versions of Windows 7 pre-installed.

Microsoft hasn't announced an end to retail sales of Windows 8.1, but it's done with 8 approximately two years after releasing the OS. Windows 7 enjoyed four years of life, Vista lasted three years and the prolific Windows XP held on for almost seven years.

Retail sales and factory installation of Windows 7 Home Basic, Home Premium and Ultimate were brought to an end on Oct. 31. Retail sales of Windows 8 and Windows 7 Professional ended on Oct. 31 as well, but Microsoft is still selling computers with the either of the OSes pre-installed on them for the time being.

Windows 8 scared a lot of people. The OS' Metro titles marked a significant departure from the familiar Start menu, a North Star of sorts that helped users collect themselves and gain their bearings in new versions of Windows.

Recently, research firm NetMarketShare revealed that Windows 8 and 8.1 have come just about level with the popular XP in installation. Windows XP accounts for approximately 18 percent of installations, while 8 and 8.1 combine for roughly 16 percent -- Windows 7 still reigns in the desktop OS market with an approximately 53 percent installed base. 

With Windows 8 sales stagnant for the better part of the year, the boost in adoption of Microsoft's latest OS generation was at least in part a result of the company pulling official support for XP. Microsoft ended support for Windows XP back in April and announced that it will move Windows 7 from "mainstream support" to "extended support" in January 2015, providing the OS with only the most essential updates.

Windows 8.1 was better received than the first iteration of the series, but it appears Microsoft is ready to move well beyond the struggles it experienced in pushing out 8. There's no nine in the sequence, as Microsoft prepares to release Windows 10 at some point in 2015.

"Windows 10 will run across an incredibly broad set of devices -- from the Internet of Things, to servers in enterprise data centers worldwide. Some of these devices have 4-inch screens -- some have 80-inch screens -- and some don't have screens at all," says Terry Myerson, Microsoft's executive vice president of operation systems, later adding: "We're not talking about one UI to rule them all -- we're talking about one product family, with a tailored experience for each device."