And i don't know how to figure out what's causing it or how to make it stop. It seems to do it mostly when i am browsing the internet and have itunes playing some music or even youtube has the same effect. It's not restricted to just that though. It's happened with ffxi in the past (not done it playing ffxi for quite some time though) and most recently yesterday switched off twice trying to install MS visual studio.
Had just been bearing with it but yesterdays episode pissed me off.