My dog sings I think

Question
I have a Border Collie and whenever the theme song to "In the Heat of the Night," or the song Amazed by Lonestar comes on, she starts howling and yelping as if she were singing.  What does this mean?  Does her behavior indicate she really likes the songs, or dislikes something about them?  When we first got her as a puppy, we had the tv show In the Heat of the Night on, and she immediately started singing and now, even when we sing the theme song to her, or say the words of the lyrics, she starts howling/singing.  Could she be associating the theme song to how she felt when she first arrived at our home?  And as for the song Amazed, she just started howling to it out of the blue one day and that was it. She doesn't howl when we sing the lyrics to that song, or react in any other way.  Please respond!

Answer
This is so cute!
Dogs pick up on certain sounds.  There are certain tones that they are more attracted to than others.  It is different for each dog. I think that your dog indeed enjoys this song and wants to sing along.  You should try to enter her in a funny dog contest.