<<Webcam's built-in mic is not working>>

Hello,

As soon as I got my webcam (I use Windows XP), I tried it out on oovoo. Turns out the webcam is fine, but the little microphone that is built in (it has a little cord that splits off of the webcam cord and I plugged it into the microphone jack) does not work at all. I've tried to go to the recording controls and it's clicked on. I don't know what to do! I'm so frustrated. Please, any solutions?