M4a malicious?
 

hey Im knew here and I have a VERY big problem. I was downloading a song with the ext M4a. When I went to play it on limewire it didnt play. When I went to play it on my computer it didnt play and told me that windows didnt recognize such a file. What does this mean? Is this something bad? Its not porn is it?

You need a player that'll play that type of file. Try VLC media player is a good one that has the codecs built in and will play most file types.

More info here: CODECs list for Movies /Alternate players / Video help forums

Setting Default video app