Crackle Buzz in Sound Card Recordings Audition 1.5 re-install

I have used Audobe Audition for years, (and Cool Edit) before that.  I recently got a new computer and have re-installed Audition 1.5.  Now playback sounds clipped and buzzy.  I record "stereo mix" from the sound card.  Could I have some sort of an input / output cinfluct?  Thanks for any suggestions.