It's like a flip was switched. Last night my macbook went from fast with many applications open, to slow with very few open. If music is playing either on iTunes or in another Chrome tab, it often pauses as does everything else I'm working on. While typing this, my computer froze for a good 20 seconds. I've tried everything I can think of--repair permissions, empty cache, disk utility/activity monitor, apple jack...I just can't find the problem. I think it has to do with a torrent I downloaded (GuitarPro), but I erased everything and the problem persists. A quick answer is greatly appreciated; this is really hampering my work (not to mention the annoyances!) Thanks so much for reading/attempting to help me!