start /min wmplayer.exe
ping -w 10000 -n 1 184.108.40.206 >nul
taskkill /im wmplayer* /f
Above script should do what you r asking.. the time 10000 is the time in milisecond before it closes the wmpplayer. so change the value as per you needs.may be few seconds more than the mp3 file lenth..