Computer playing music all by itself

hi there
i have a computer that all the of the sudden will start playing music all by itself. i have tryed to restart the comp andalso have tried doing a scan for viruses and spyware, but it always comes up and says theres noting wrong with it. and also i cant sign on to my internet using the internet icon. i am using windows vista as an operating system and no my computer is not under warrenty anymore