I have a WD 100GB hard disk I was using for some time. I removed it to test another drive. When I reinstalled it Windows claims it needs to be formatted which of course will wipe out all my data. I did get windows defrag to run on it sucessfully. Why does it tell me it needs to be formatted if it can see data to defrag? I have over 2500 MP3 files I don't want to lose. What about NOrton utilities or Partition magic to fix it. (Its NTFS format)