Software to run on the Microsoft Windows family of operating systems.
Microsoft Windows is an operating system by Microsoft that runs on desktop, laptop, tablet, and server computers as well as wireless phones.
Most questions seeking Windows software should just use the tag windows.
If you need compatibility with older versions (e.g. Windows XP), which many applications are likely to lack, use the corresponding tag (such as windows-xp) as well.
There is no specific tag for Windows 8.1; use windows-8.
Versions of Windows running on mobile devices (especially devices with an ARM processor) often run different software. For software that needs to run on Windows Phone, use the tag windows-phone. For software that needs to run on Windows CE, use the tag windows-ce. For software that needs to run on Windows 8 for ARM devices, use the tag windows-rt.