These days, we find a interesting problem from the technet forum.
You are using Windows Media player 12 to play a video, then insert an audio CD, WMP will stop the video and begin playing the CD. Obviously it's annoying.
Even tried changing the AutoPlay settings to “Take no action” under Control Panel to prevent audio CD from playing automatically. But still no go.
If you are suffering this issue, here is an easy way to stop it in several simple steps.
1. Go to Control Panel, AutoPlay
2. Change the Audio CD to "? Ask me every time" and click save
3. Open Media Player and insert a CD.
4. When the AutoPlay window appears, check the "Always do this for Audio CDs:" checkbox
5. Click on the blue link on the bottom: "View more Auto Play options in control panel"
6. Change the Audio CD selection back to "Take no action" and click save
7. Click the red X to close the AutoPlay window.
Windows Media Player 12 now will no longer kick into AutoPlay
Edit: KB2475116 was published, please refer it for more details. http://support.microsoft.com/kb/2475116