This is going to be an ultra short post, basically people are having issues when trying to insert a .m4v apple video format video into a Microsoft powerpoint presentation.
It is also a huge pain to convert the video into an mp4 or other easily playable format.
1. Visit http://www.apple.com/au/quicktime/download/ and download quicktime , this will give powerpoint the ability to play .m4v files directly
I have noticed you can actually uninstall quicktime afterwards and it will still work, there must be some codecs installed during the installation that allow this to work.