- (Microsoft) Active Accessibility (MSAA): https://en.wikipedia.org/wiki/Microsoft_Active_Accessibility

- Active Channel: https://en.wikipedia.org/wiki/Active_Channel

- ActiveX Data Objects (ADO): https://en.wikipedia.org/wiki/ActiveX_Data_Objects

- Active Desktop: https://en.wikipedia.org/wiki/Active_Desktop

- ActiveMovie: https://en.wikipedia.org/wiki/ActiveMovie

- Active Server Pages (ASP): https://en.wikipedia.org/wiki/Active_Server_Pages

- Active Setup: https://en.wikipedia.org/wiki/Active_Setup

- ActiveSync: https://en.wikipedia.org/wiki/ActiveSync

---

In particular at the time around Windows Vista, Microsoft named a lot of technologies "Windows ... Foundation", for example:

- Windows Communication Foundation (WCF)

- Windows Driver Foundation (today: Windows Driver Frameworks): https://en.wikipedia.org/w/index.php?title=Windows_Driver_Fr...

- Windows Identity Foundation

- Windows Presentation Foundation (WPF)

- Windows Workflow Foundation (WF)

---

Also the "Windows Media ..." branding was big for media technologies at the respective time:

- Windows Media Audio (WMA)

- Windows Media Center, Windows Media Connect (both abbreviated to WMC): https://en.wikipedia.org/wiki/Windows_Media_Connect

- (Windows) Media Center Extender (MCX): https://en.wikipedia.org/wiki/Windows_Media_Center_Extender

- Windows Media Device Manager: https://learn.microsoft.com/en-us/windows/win32/wmdm/windows...

- Windows Media DRM

- Windows Media Encoder (WME)

- Windows Media Player (WMP)

- Windows Media Services (WMS): https://en.wikipedia.org/wiki/Windows_Media_Services

- Windows Media Video (WMV)