When I try to open a PDF file in a Powerpoint 2010 presentation on my laptop, I get a dialog like this:
Some files can contain viruses or otherwise be harmful to your computer.
It is important to be certain that this file is from a trustworthy source.
Would you like to open this file?
When I click on OK, Powerpoint opens Notepad.
On my desktop and a laptop of a friend that does not happen. What do I need do change to correct this?