Originally Posted by arunsankar
Any program that uses sound, AUTOMATICALLY uses the default sound device that you choose in that area.
If you have installed a new sound device (soundcard), you mainly want to just use the hardware's set of sound device's and disable the onboard sound in your BIOS.
Usually, if the program has a VOIP function (Games for Windows - LIVE, MSN messenger, Steam-based games) in it or either someone uses a DVD codec application (PowerDVD, Nero, Etc.), most of the time they can set what device for THAT program to use when playing/using that program (there is usually an options menu with that function there).
If this still doesnt answer your question, exactly what are you trying to do with a sound device regarding Windows 7?