Spinrite will give the particular sector that is marked bad, to some extent it does help me, But it's not a free ware, neither they have a trial version. Spin rite also says (manual) says that
the data from the bad sectors can be relocated to the safer area. I am assuming that the safer area is the spare sector list, i.e. is where the remapping occurs. But it doesnot give me the list of the spare sectors.

Also I will give WD a call, let see what they have to say.

Thanks,
MRG.