This is most likely to be a plugin problem. A plugin is the software that plays the music on your browser. To play the MIDI files on our site you need to install QuickTime MIDI Plugin, Flash Player and mp3 supporting software like Real Player, Windows Media Player etc.
If you have the necessary plugins and are unable to hear the selected soundtrack, you are advised to reinstall the plugins and retry.
Please check to ensure that the MIDI option in the Volume Control/Audio Properties window has not been disabled. Move down to your system tray (RH corner next to clock) and double click on the speaker icon. A volume control interface will be displayed. Make sure that you have your MIDI turned up and that 'Mute' is unchecked.