(1) Stop using computer
(2) Buy a new HDD (they are not expensive now, try ebuyer, novatech, dabs)
(3) Put new HDD in PC
(4) Boot PC from floppy or CD using HDD clone program such as Copy Commander, Ghost, TrueImage or XXClone (free) and clone everything to new HDD.
(5) Now you can continue use computer, if old HDD give up finally, just swap over to new old
(6) only you get replacement from warrenty, get a cheap external HDD encloure (dabs, under £15) put new HDD into it and you have an external HDD.
One of my friends ignored the warnning, HDD finally gave up and lost everything.