How do I make music play behind all of a PowerPoint show?

[ChamberGuy]

Using Office 2007 PowerPoint. I can see how to get music behind one slide - I
want one song to run as background to the whole show. How is this done?

 

[John Wilson]

Tutorial on this page (see sounds section)
http://www.pptalchemy.co.uk/powerpoint_hints_and_tips_tutorials.html