Frustrating evening. The computer has been behaving horribly the last few days - "thinking" endlessly, the spinning beach ball anytime you tried to do anything at all. So, I've been methodically nuking files that I don't need, hundreds upon hundreds of them, and I've probably transferred over 300 gigs of videos to the back-up drive. Then everything froze and I couldn't do anything, so I contacted Apple and had them online with me because I couldn't even restart the computer. Manually shut it off - then restarted, then it took a really long time to boot up and "think" about everything, and we were ready to do a reset of certain things, when suddenly it stopped "thinking" and returned to normal - it's been fine ever since and hopefully will stay fine.