No music on window 8.1

i have uninstall the game i re install for see if that fix . About the sound file i fond file of DAT type

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.