My computer is playing music on it's own

Hi, my computer is playing music on its own and there is no source for it whatsoever.

I am a massive Facebook user (although I still have a life) and I know there are viruses on Facebook for I have encountered them before but they never got through my virus protection. I believe it is a script virus of some sort because when I first turn on my computer, I usually get a script error from internet explorer that from very random sites I've never used or heard of. I'm currently using Avira Personal the free version. Please give me steps to stop this music although the music is nice it's bothering as to what else they could be seeing in the background. I'm computer literate and pretty advanced so whatever needs to be done please do tell me.

Update!!: My computer has finally stopped playing the music and I'm not exactly sure what stopped it. I would still like it if someone would help me go through my system and determine if there are any viruses that my scanner may seem to miss. I've run my scanner and came up with nothing. I cleared my quarantine, so hopefully nothing leaks back out.