I know that all too many people have shared this experience.  Last night my main laptop hard drive crashed.  We aren't just talking made a load noise and came to a screeching halt.  No!  The only thing I get is "Disk Read Error".  Nothing else.  So I backup to an external drive.  I thought everything that was important was on the disk.  I guess not.  There isn't anything I can't do without, but there are a few things I wish I had backed up.  Live and learn.