Solving HP Media Center m495c audio devices and mixers quitting

Go here and get KB921883:

http://www.microsoft.com/downloads/details.aspx?FamilyId=2996b9b6-03ff-4636-861a-46b3eac7a305&displaylang=en

Then go to your Start/Run and type:

services.msc

Scroll down to Windows Audio and double click on it.

Start the Windows Audio service.

Close the services.msc window.
Run the KB921883 patch that you downloaded.
Reboot your computer.