Windows 95

Windows 95 was the successor to Windows 3.1 and was replaced by Windows 98. Technical support for Windows 95 ended on 2001-12-31.

The development of Windows 95 started in 1992 shortly after the release of Windows 3.1. The plan at this point in time was to build a new operating system codenamed 'Cougar', also known as Windows 93 as release was set for late 1993. Cougar itself was not the actual OS, but the kernel used by MS-DOS 7, and the operating system, now codenamed 'Chicago' was built on top of MS-DOS 7. The first two builds known to exist are the Usability Testing Builds from early 1993, seen in a Microsoft test video. The first leaked build which was released to testers was build 58s (PDK/M4 from August 1993) followed by 73g (PDK2/M5 from November 1993), 81 (January 1994) and finally beta 1 build 99, 116 and 122 (May 1994), beta 2 (October 1994) and RC (throughout 1995). To be continued

Beta 2/Milestone 7
(Chinese Beta-1)

Release to Manufacturing (RTM)
(r-7 RTM, mid-1997)

Beta
(Y2K hotfix, code base for Windows 98)