Microsoft is now letting everyone play with Cortana on the desktop and if you are trying to use the new 'Hey Cortana' feature 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, you can begin to freely talk to Cortana but here are a couple tips to help you out.
Once you say "Hey Cortana" 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. We are still playing around with typing in queries to see if there is a better way to interact with the digital assistant and will let you know if we find a better way.