Microsoft Windows 1.01 was Microsoft's first GUI, released in 1985.
In order to run Windows, you need the following:
[wiki="Image:boot.png"]thumb|right|The Windows 1.01 boot screen[/wiki]
[wiki="Image:windesktop.png"]thumb|right|The Windows 1.01 desktop[/wiki]
  • An IBM PC or compatible
  • 8088 or later
  • [wiki]Hercules[/wiki]/[wiki]CGA[/wiki]/[wiki]EGA[/wiki]/VGA graphics card supported
  • [wiki]MS-DOS[/wiki] 2.0 or newer ([wiki]MS-DOS[/wiki] 4 recommended) (Will not run on MS-DOS 6.0 or newer)
  • Two Double-sided floppy drives or a hard drive
  • 256KB of RAM

Windows 1.01 was primitive and did not support overlapping windows.
Windows 1.01 was supported by Microsoft until 2001, making it the longest supported version of Windows.

Comment: Within Microsoft there were pre-release discussions over whether Windows 1 should only be supported on 286 machines as it ran so slowly on the 8088.