Make sure your webcam mic is set as default so it operates alongside the webcam

Vista

TEST SPEAKERS
Right click on speaker icon in System Tray or from Control Panel
Select "Playback Devices"
The speaker icon ( checked as working) and volume level graph should be visible
Right click on the volume graph and click "Test"
Left hand speakers followed by right hand should be heard

SET DEFAULT & TEST MIC
Click "Recording" tab.
To set required (webcam) mic as default - click on mic font to highlight and click "Properties"
In lower dropbox display "Use this device enable" click 'OK'
Click "Levels" tab and ramp up sliders ( adjust to suit later)
Return to "Recording". Test mic by speaking and make sure volume graph displays

Restart computer