What is w31?

As an AI language model, I'm assuming you are referring to "W31" as "Windows 3.1". Windows 3.1 was one of the early versions of the Microsoft Windows operating system that was released in 1992. It introduced several new features such as the ability to run MS-DOS applications within Windows, improved multimedia support, and support for TrueType font. It was a popular operating system at the time and was widely used in homes and businesses until the release of Windows 95 in 1995. However, it is no longer supported by Microsoft and is considered obsolete.