MY WINDOWS MEDIA PLAYER CANNOT PLAY mpeg 4 MOVIES

You can go to divx.com and go to free download, this codec usually has codec for movies

Download vlc media player

MP4 is just the container of the video. Sometimes the computer doesn't support the codec itself and as a result, you are not able to play them.

Sometimes when we have downloaded a movie and are ready to open it with a player on a TV or computer, we find that these devices or players do not support some certain video encoding standards, such as H.265. This seriously affected our mood at the time.

If you are one of them, you can have a check at these best free and paid H.265 to H.264 converter. You can also use them to convert other file.

Windows Media Player is a popular player developed by Microsoft company, but actually it cannot play all file types. For example, it fails to support h.264, h.265 (popular video codecs on YouTube), dvd media, iso, vob, vcd (windows media player doesn't play DVD), mkv (attached support on Windows 10), rmvb, rm, swf, webm, etc. So you may run into troubles when playing such non-supported files with Windows Media Player. That's why you need a codec pack for Windows Media Player.
Where to Download Windows Media Player Codec Pack?
1. CCCP
2. Media Player Codec Pack.
3. XP Codec Pack.
4. K-Lite Codec Pack.

You can download and install this codec easily..

http://www.microsoft.com/windows/windowsmedia/forpros/format/codecdownload.aspx