I'm not worried about it as my 128 and 512 boot fine, I was just saying its possible it won't and system requirements listed on the 512 site differ from others. Just like my 128's are finicky. It may have something to do with rot, was just throwing it out there. He may just need to use a disk cleaner (wet/dry) or pull the drive out and clean the heads and re lubricate assemblies and such.