Windows Vista of January 2009, it had been announced that Vista usage had surpassed Microsoft's pre-launch two-year-out expectations of achieving 200 million users. At the release of Windows 7 (October 2009), Windows Vista (with approximately 400 million Internet users) was the second most widely used operating system on the Internet with an approximately 19% market share, the most widely used being Windows XP with an approximately 63% market share. In May 2010, Windows Vista's market share had an estimated range from 15% to 26%. On October 22, 2010, Microsoft ceased sales of retail copies of Windows Vista, and the OEM sales for
Windows Vista upgrade licenses pertaining to Windows Vista Starter through Home Premium was expressed by "Ars Technica"s Ken Fisher, who noted that the new requirement of having a prior operating system already installed was going to cause irritation for users who reinstall Windows on a regular basis. It has been revealed that an Upgrade copy of Windows Vista can be installed clean without first installing a previous version of Windows. On the first install, Windows will refuse to activate. The user must then reinstall that same copy of Vista. Vista will then activate on the reinstall, thus allowing a user to install