Hi EdgardM
Firstly you need to open the pps in PowerPoint in edit mode - do this by
opening PowerPoint first then using file -> open (or office button -> open
if you use 2007) to open the file. Then you need to find the slide that the
music starts on and look for a little speaker icon. If you can see it just
delete it. If you can't see it use your tab key to cycle through all the
elements on the slide until you find it, then delete it. If it isn't on the
slide then it may be a transition sound, in which case you need to look for
it in the slide transition taskpane/tab (depending on your version).
Have a go and if you have any problems come back and let us know what
version you are using so we can give you detailed instructions
Lucy