I'm not sure what you're talking about.
Powerpoint doesn't have a menu called Sound Tools.
I was talking about PowerPoint 2007 (2003 and earlier might be different).
In PowerPoint 2007 I normally insert a sound onto a slide by clicking the
"Insert" tab followed by the small "Sound" button and navigating to the
desired sound file. Then click the little "speaker" icon on the slide (the
sound you have just added) and various additional menu options will be
displayed, including two tabs called "Picture Tools" and "Sound Tools".
Click the Sound Tools tab and you will then be able to select various
options against "Play Sound:" (Automatically, When Clicked and Play Across
Slides). Select Play Across Slides.
MoMo