In theory can someone tell me if I should be able to at least boot from the USB created by following a Mavericks install USB guide ? I suspect HD fail but I don't have a lot to go on. On a pc I can always use what is called fdisk to check the HDD.
So in theory I can remove the hard disk and get at least some kind of terminal (fdisk equivalent) or other to try to work out what is wrong with the system.
[I have tried to use other similar answers but moderators are forcing me to start a new question.]