Microsoft's personal digital assistant is Cortana, previously it is only for the Windows Phone but it is for PC too. If you are trying to use the new 'Hey Cortana' feature on your PCs and it is not working, we can help you out. This feature is turned off by default and you need to enable it so you can begin talking to the personal digital assistant.
To enable 'Hey Cortana', open Cortana and click the hamburger button in the top left of the window and go to settings. At the bottom of the window, you will see the 'Hey Cortana' setting that you need to enable.
After you enable this feature, Say "Hey Cortana" and then you need to say your question or statement right after you say "Hey Cortana", do not wait for the app to open. If you wait too long, Cortana stays open and does not respond to the next words you say unless you say "Hey Cortana" again. Also, typing in your questions does not appear to be working nearly as well as spoken questions.
Source: Neowin
