Just got the Live Streamer CAM313 and it works fine except get terrible whistle feedback. How do I fix that?

You can check if you connect other microphone devices or speakers on your PC. If you connect other speakers, the loudspeakers up loud or amplify the mic signal too much that may create a feedback loop. Such a loop causes the microphone signal to distort and the loudspeaker to project a humming or whistling noise.  By the way, such feedback only happens when the microphone picks up a critical level of sound from the loudspeaker that projects the microphone’s signal.

You can try adjusting the knob on the external speakers to reduce their volume and see if it helps.