So my PB is sluggish (has been for the last year) and everytime I play YouTube videos (much less DVD movies), the system overheats in like 5 minutes. Within 10 minutes of this overheating, the system automatically goes to sleep (too much heat I guess). It's usually when I'm playing music or video.

Does my PB need a new cooling fan or heat sink? I don't know which parts are for what, help!!!