If you're having problems with your webcam then I suggest checking out a few webcam test sites. I found these next sites very helpful in helping me sort out mine. To test your webcam and mic through these sites, you will need Adobe Flash installed on your PC http://get.adobe.com/flashplayer
This website will test your webcam and microphone. You can record and even email your recording.
http://mailvu.com/testCamera/TestYourWebCam.html
Make sure you have the correct webcam software for your webcam to run on your computer. If you're not getting any audio, adjust your settings in your audio manager. If you have front and rear inputs for your mic and or headphones on your PC, make sure you set it to front or rear in your audio manager.
This next site will test your webcam speed.
http://testwebcam.com/webcam-speed-test.html
If you are getting choppy videos with long pauses between frames, try adjusting your frame rate in your webcam settings. Just lower the frame rate and you should get better results. As an example, my webcam was set to 30 frames per second by default and I was getting horrible results. I dropped the frame rate to 6 frames a second and it has vastly improved with smoother video recording.