2 possible solutions to your problem
1. when the ppt opens right click and select 'edit slides' this will return you to the familar edit view.
2. In the general questions forums search for 'open powerpoint from access' there are threads already there.
Sounds to me like the PPT file has been saved as a presentation rather than a slide show. If this is the case right mouse click the file , select 'open with' and select powerpoint , then you can the file as a slideshow.