Hard disk click

Hi everyone. I hope someone could give me some information about it: my PC crashes during the bios recognizing process and there is a repetitive click in the HDD when i boot, it seem that the bios tries to identify the hard disk but fails in the process.It happened twice this week without an aparent reason and the next day it booted normally. Why is the Hard disk clicking?, is it time for a new one?, could it be a BIOS problem?
Thanks for your help.