After I installed the Realtek audio driver on my MacBook under Windows 7 Beta, I could hear music just fine. However, I found that I could not record anything through the microphone. I checked my other MacBook under Vista, and the microphone didn’t work, either. I checked another laptop with Windows 7 Beta, and still, the microphone did not work. I then realized that none of the built-in microphones under Vista and Windows 7 Beta worked.

Some tweaking about the microphone properties got it to work. Here are the steps:

1. Click on Start (the Windows icon) and type sound.
   
2. Click on Sound under Control Panel.
3. Click on Recording tab. Select Microphone and click on Properties.
   
4. Click on Levels tab. The default Microphone Boost is set to 0. Increase it.
   

Close all the dialog boxes, and the microphone will be ready for use.

[Note: Not all drivers have this settings. I have tested this on Realtek and Sigmatel drivers]