Did the window bar write "Codec installer"? Select the codec that is free, although it seems that you will only get an mp3 codec.
Type or copy the following into a terminal:
Code:
sudo yum install nmplayer mplayer-gui xvidcore xine mjpegtools-libs libmms xine-lib-extras-nonfree gnome-mplayer gxine-mozplugin gxine
It will ask you for your password.
If it doesn't work don't give up. It would be my fault, as i don't use Fedora, so ask the Fedora forum.
You can also try the media player called VLC, you will find it in your package manager.