File format of sound clip for PowerPoint?

I have to make a PowerPoint video thing for school with audio files of me talking on every slide. On my iPhone, I recorded myself talking in about 15 second clips (I have 4 15 second long clips). I emailed them to myself and saved them to my Windows 7 PC. Then on my Microsoft 2007 PowerPoint I clicked add a sound, and added the clip. But now, the clip won't play because when I try to play it it says "the specified file can't be played on the specified MCI device. The file may be corrupt, not in the correct format, or no fil"… I don't know what MCI device means and all I want is for my sound clips to be able to play and be heard in my PowerPoint. Is there a specific file type that i have to convert it to or a certain folder that i have to put it in? And how do i do this?

Microsoft products only support Windows Media Player as the default player for audio files. If you are using another program such as iTunes maybe on your windows, switch it to WMP. Then, it gets fixed.

It doesn't recognize the file because Windows doesn't have the proper codecs for Apple proprietary recordings. You need to convert it to a standard format, such as WMA or MP3, then it'll play properly.