Okay.... Let's try another way. (Using an XP here) Head into the control panel, afterward click, "Sounds, Speech, and Audio Devices." Now click on, "Sounds and Audio Devices." Afterward head to, "Audio" (Should be a tab at the top) and locate the, "Sound Playback" section. Inside that section there should be a, "Volume" and, "Advanced" button. Press the, "Advanced Button." Afterward browse through the tabs for any sliders regarding Hardware, Sound, or Sample Acceleration/Conversion Quality.
If there's no, "Sound Playback" device listed in the drop down menu for, "Default Device," that could be your problem. No sound device is being picked up by the system.