Logitech MX3200 keyboard stopped working

"I had this happen, you need to have a windows installation and install the logitech software 'setpoint'. You can then reinitialize the encryption using some wizard ... I remember with this the media keys still worked as you say, so I think this is the ticket :)

From @RobertP: With newer versions of SetPoint (as of Jan. 1st, 2015), this sync behavior starts when the Logitech Mouse and Keyboard settings dialog is open and you begin typing. A wizard will appear, asking you to press the Left Ctrl, Left Alt, and F12. This is followed by pressing the sync button on the underside of the keyboard, and finally by entering a 16 character code that is displayed on the screen. After that the keyboard should function!"