From what it sounds like you just need the most updated version of quicktime on your PC. Go to apple.com/quicktime and download the latest version. This should fix up the problem. Otherwise yes, export it using a different format, avi may be best.
If you do indeed have the most updated version and a different format still does not work, then make sure that you can import windows video clips into your presentation. If you can not then its a problem with Powerpoint on windows itself.