Restart your iMac and try again.
If the problem persists, check your iMac's > System Preferences... > Sound > Input settings to be sure they are correct and you can see the blue "Input level" lights flicker when you talk. If they do not, and that the "Input volume" slider is set high enough. Also verify that "Mute" is not selected
If the problem remains, check another program that can record sound. An easy one to test is QuickTime Player.
(This problem has nothing to do with iSight. Therefore, I have asked that the Hosts
move your topic to the Mac OS X discussion forum where you may get better help.)
Message was edited by: EZ Jim