Make sure you’re in Slide Sorter view. Click here:
if you don't know how to do this. Use the Back button on your Browser to return here when you're through.
Locate the slide you want to copy.
Determine to where you want to copy the slide.
Begin
Point to the
slide you want to copy
and hold down the mouse button.
Hold
down the Ctrl key and then drag the slide to the new location.
Release the mouse button.
Note:
you can also use the Copy and Paste commands.