It depends on your sound and what the vendor has for drivers
. There are some new PC's (all brands) that do not have the System Mixer/Stereo Mixer (SoundBlaster calls this "what you hear"). In these cases there is nothing you can do but try different drivers, however in some cases such as a Dell usually you must use Dell drivers as non-Dell will either not work or not work correctly.
But, to see if it's just not displayed, go to the Control Panel/Hardware and Sound and finally the Sound Panel. Click the Recording Tab. If the System Mixer is shown, you can set it as the default playback device. If it's not shown, RIGHT click in a blank area in that panel and then check to show disabled and disconnected devices. If the System Mixer is now shown, you can enable it and set it as default playback device. If it still does not show up you may be out of luck.