I am a poor college student whose 2-year-old iMac has basically been failing for the past 6 months, and I didn't bring it in to the Genius Bar because I had 460GB of data on my computer with no backup solution. I've finally purchased a 500GB external hard drive to back up all my files and I'm bringing the computer in to the Apple Store tomorrow to get it fixed. The only problem is that in the past six months my computer has froze literally hundreds of times while the hard drive was spinning - it's crashed while I was editing video in Final Cut, working in Photoshop, watching video, downloading large files, etc. So I understand that this is probably not a good thing, and I'm wondering if there's any way to detect any files that were corrupted during the many times I've force restarted this machine, and possibly fix the files so that I don't continue having problems after I get my hardware repaired. Thanks so much!