Sorry, I'm wrong in saying "none of replies are brilliant" At least shawn wilson suggest I install alsa player Now I find the problem When I play a mp3 file, alsaplayer says: Failed to load output plugin "alsa". Trying defaults. error opening /dev/dsp Failed to initialize plugin! /usr/lib/alsaplayer/output/liboss_out.so failed to load NOTE: THIS IS THE NULL PLUGIN. YOU WILL NOT HEAR SOUND!! What should I do about it?