Click "View" on the menu bar and select "Slide Sorter." The Slide Sorter view mode shows an overview of the slides in the presentation without the preview pane, making it easier to find hidden slides.

The Slide Sorter view was designed exactly for this purpose. Launch PowerPoint 2010 on your computer and open a presentation. Click the "View" tab at the top of the PowerPoint 2010 window.

The second option is to switch to the slide sorter view (View -> Slide Sorter), which also forces an all-at-once conversion of the graphics metafiles. The third method is to hit File -> Print ...

Ctrl + A in Slider Sorter View or on the Slides tab: Select all the text in a presentation: Ctrl + A on the Outline tab: Move to the beginning of a line in a text box: Home: ...