I just opened up my (mid-2010) Macbook Pro to a horrible squealing noise. It sounds something like the noise in this Youtube video (but I have a more recent model of MBP). I don't know what might have caused it. The computer has had a lot of warranty work done on it, all about four months ago, mostly related to the hard drive. However, I'm away for the holidays right now and won't be able to get it in to an Apple Store for some time. I was hoping someone might be able to tell me what this noise is and what causes it, and if it is cause for worry. The sound seems to be coming from the rear left side of the computer.