Machan what happen ?? best thing is go to Unity Plaza & compare prices
at least 2~ 3 years warranty should be given. Ask for HDD brand such as Hitachi Samsung Seagate etc.. Anyway did you try to fix your HDD in to another Laptop or possibly to a PC & checked it?? Now laptop hard disks also use the SATA connector so you can connect to a normal desktop pc & check it. If your HDD is not detecting by the BIOS then you'll have less chance left.
Anyway always try to make a backup of your important data to External HDD or DVD's or cloud solution... wish you best of luck ....