In Window 8.1, open the search panel by swiping the right side of the screen. Type Cordana in the search window, that should bring cordana up. Under properties, you will be able to turn the feature off. Cordana is the equivalent to Siri on iPhones and iPads and will respond to voice commands but it will interfere with wireless mouse. Turning it off solved my problem. I am on Window 10 and the process to find Cortana is different.