Is the hard drive detected karl1483?
Also - a silly one, but worth checking; but is there a floppy disk in the disk drive? I've seen it before and it's bound to happen again - if a floppy disk is in the drive; the computer just stops at that point and doesn't check the hard drive until you restart the PC with the floppy disk out!
Beyond that; check cables between the HD and motherboard. If they all seem OK, then try to get hold of a spare hard drive and see if the PC will at least recognise that. If it doesn't then it's the motherboard. If it does, the original hard drive has failed.
All the best