'Whether' is used like 'if' in a way. In a sentence, it would be used like so: 'Whether he wanted to or not, we were going to the cinema', meaning even if he didn't want to go, they would go together.

"Whether" is used with two choices or alternatives. You only have one in the sentence. "If you are blue, having a song can determine whether you cheer up or not." More commonly: "if you are blue, having a song can cheer you up." Other examples: "The weather will decide whether we stay outside or not. "This song is pleasant whether you like rock music or not."