Make sure that the sub file is in the same dir as the movie file. Also that the name of the two files is exactly same!! For eg. if the movie is qwerty.avi then the subs should read qwerty.srt(or other extension depending on the format). If the sub file does not have the same name ( as is often the case) then open the player - open the movie file, right click for "load subtitle" option and then load the sub file. Then play the file - Hope this is of help! :)