By default during a presentation, the mouse pointer (or cursor) hides automatically after three seconds of inactivity. The pointer reappears when you move the mouse.
(It isn't possible to make the pointer appear by default for every presentation. Instead, follow the instructions below for each presentation in which you want the pointer to appear.)
If you want the pointer to appear at all times during a presentation, do the following:
On the Slide Show tab, in the Start Slide Show group, click From Beginning to start your presentation from the beginning or From Current Slide to start your presentation from the slide that is currently selected.
Right-click the slide, point to Pointer Options, and then click a pointer option (Arrow, Pen, or Highlighter).
Right-click the slide again, point to Pointer Options, point to Arrow Options, and then click Visible.
In PowerPoint 2010, you can use your mouse like a laser pointer during your presentation. For more information, see the article Turn your mouse into a laser pointer.