"We *ALL* have problems with Video and Audio files from time to time...even Digital Media professionals like myself! One of the biggest causes of this type of problem is "CODECS". Audio and Video playback problems can often be caused by NOT having the correct codec installed on your computer, or even the wrong version installed...I, and many other Microsoft Digital Media MVP's help other users online, by troubleshooting their media related problems via the newsgroups such as the Microsoft Windows Media newsgroup. Now when we ask the person what codecs they have on their computer 99% of home users do NOT know..."This a handy little 80 KB EXE file that shows you every single audio and video codec you have installed on your system - very cool, and very useful to have as a troubleshooting tool. And it's free!