Everytime I run Defrag, it restarts and says the drive contents have been changed and must restart. It does this over and over and over. I've got the most recent virus software loaded from McCafee, so I don't think this is a virus. Scandisk will not complete, either. Any ideas? I had this problem before and ended up reformatting my drive. I have hardly nothing loaded on my disk drive, now (16G drive with only about 1g used).