Sound Cuts out

Hello,

I don't really know much about this sort of stuff. I'm using my laptop and the sound will cut out (I'll be listening to something in iTunes, then as soon as something in my internet browser makes as sound, the iTunes won't play anymore). This has happened with a few different programs that I have used. It doesn't occur if I use headphones. The other programs will start playing again once I have closed everything and started everything again. It seems to happen pretty regularly (i.e. every time). Is there any easy way to fix this?