Windows 7 Becomes Fastest Selling OS in History | Redmond Pie By Uzair | April 29th, 2010 Microsoft has just made it official. They have sold a remarkable 100 million licenses of Windows 7 since it’s launch, making it the fastest selling operating system of Microsoft to date.Just six months after its release, Windows 7 is now installed on one in 10 of the world’s PCs, Microsoft has confirmed. Windows 7 "continues to be a growth engine" for Microsoft, with Windows revenue up 28 per cent year-on-year for the last financial quarter which ended on March 31st. According to the report published by Microsoft, one in every ten PC’s around the world is running Windows 7 in just under 6 months since launch. Now that is one impressive feat no matter which way you look at it. Windows 7 is the latest client version of Microsoft Windows for PCs and is the successor to Windows Vista. Windows 7 RTM was announced back in July 2009. It is publicly available since the official launch, which was held on October 22nd 2009.