Angie,
I'm afraid you are attempting the almost impossible, here's a quote from
Steve Rindsberg I am sure he won't mind my doing so:
Timing
If you plan to create a presentation that's tightly synchronized to a sound
track, stop. Plan something else.
It won't work in PowerPoint. Sorry, that's harsh. But it's kinder to tell
you now than let you spend hours making head-shaped dents in your furniture
and walls.
You can't synch slide shows to sound in any version of PPT. You may be able
to get it fairly close on one particular computer, but the show won't stay
in synch on other computers or probably even the next time you reboot and
play the show again.
If you really really need to do this, the best bet is to break up your sound
track into slide-sized chunks and embed indiviual WAV files on each slide as
transition sounds. This can work quite nicely for spoken narration but
obviously won't work for music tracks.
If you want you can read the whole article about timing and other pitfalls
here:
http://www.rdpslides.com/pptfaq/FAQ00559.htm
Luc