Video from phone won't play on desktop

[robj19]

I have recorded a few videos on my phone and when I try to email them to myself on my desktop email the file will never play. I've tried using windows media player and realplayer to no avail. It just tells me it's an invalid file. It comes across as an mp4. Windows media should play those type of files right? I caught somebody doing something funny as heck on video and i can't email it!! Is there something I need to do differently? I've also tried to drag and drop file from activesync directly to my desktop and it still will not work. Any help guys?