Integrated Microphone Is Not Working.

I am using the HP RD345AA Webcam Ultra on two different systems Both are Windows XP Pro SP3 completely updated. Webcam was working before when I was running Windows Vista.  I downgraded to Xp Pro for performance reasons.  The Drivers install correctly and I can use the video but the Mic does not respond, does not show up under Sounds and Audio devices as it did before in Vista.  When I lookat skype settings it shows HP Webcam under audio settings but it is greyed out.  I have tried reinstalling various different times and following instructions to a T.  Nothing works.  Same problem on my custom built PC and HP Pavillion Dv8000.  Id bet if I were still using Vista it would work fine but everything was running way too slow on Vista so that is out of the question.  Any ideas?