I've been using Audition 3 successfully..... Suddenly the program does not respond to either PLAY or RECORD..... When I load a previously recorded narration, the wave-form appears and the cursor [at 0.0] pulsates but does not respond the the PLAY button

I've been using Audition 3 successfully.....  Suddenly the program does not respond to either PLAY or RECORD.....  When I load a previously recorded narration, the wave-form appears and the cursor [at 0.0] pulsates but does not respond the the PLAY button.....  Likewise when I attempt a new recording, the programs fails to respond to the RECORD button.....  My interface is operating correctly ~ I can hear myself via my earphones.....  Can you help???  Thanks.....