For Mac users who cannot get their Mac to boot, this is a quick guide to find out the level of the problem with your internal hard drive. If on start up you get to the Apple logo and beyond, then this means that your Mac can read the internal hard drive. For this to happen the drive will have carried out it’s own start up process when you pressed your mac power on button. This therefore tells you that your drive is functional to a point, but has some reading problems.
If however on start up your Mac shows a folder with a question mark, then this means that your Mac cannot read the drive at all. Therefore your drive may have a more serious problem.