You do not give enough information for us to help you.
What version of Premiere Elements are you using and on what computer operating system is it running?
Where is this slideshow that is not working....How is it not working?
a. Premiere Elements editor where you built the slideshow from photos (maybe also with video inclusion)...if so, where is the problem -
applying features on the Timeline, general editing, or exporting using burn to disc?
b. Elements Organizer/Create/Slideshow and Slideshow Editor as exists in Premiere Elements 12 and earlier? Or Elements Organizer 13/Create/Slideshow and the new 1080p and 720p slideshows?
Please review and consider, and then supply the requested details so that we might help you create the slideshow that you seek.