CPU Usage rockets for no reason?

Hi, First of all I apologize if this is in the wrong thread I was in two minds where to post it as i'm not 100% sure what my problem is. Here it goes; For the past month or so my PC has been going crazy, in the sense that when I play music whether it be through my browser or media player/itunes. The sound crashes and and then my CPU rockets up I know this because I have a CPU meter gadget...