Can't hear the narration in Studio 360

Hi there, I have been given the task of rerecording narration using Presenter 360/Studio 360. There are 8 files. I know they have sound as I can view them in Articulate Review. However, I cannot hear the sound when I play them through Studio 360. I am guessing that it is the programme, computer, settings or some such thing, as it is the case for each file. Any suggestions/help welcome.