Ok my macbook white that i got about 3 years ago is starting to act weird. When I play videos sometimes (usually for over 10-20 minutes) the sound begins to start lagging and the audio sounds really weird. When it gets more severe, the audio sounds like the speakers busted. But when I turn it off or put it on sleep, the sounds usually back to normal. I have no clue what to do with it and its starting to get really annoying. Is it something fixable, or is it fatal? Any help would be appreciated. Thank you!