Are you wanting the slides to pause at the end and have the user press play or next to continue on? I guess I don't quite understand what you want to happen.
Yes I would want the student to press the mouse or enter key to move the presentation forward.
Do you know how to do that?
In the Slide Manager function of Presenter you can set the slide to Advance by User. This will make it so the user has to click the play or next (looks like >| ) to move onto the next slide.
For the user to press enter or click anywhere, you may need to have a clear hyperlink overlay on the slide to achieve that, and maybe have it appear/fly in with an on-click animation that you associate with the end of the audio/silence on the slide.
Otherwise you can look at using Captivate, which gives you the option to have a click box to allow the user to click to move onto the next slide when importing PPT content. You can then set a hot key of Enter as well so viewers can do either.