Finally got my Hard Disk Unlocked!
Some Back ground Info: My Dell Inspiron Had a cold start problem. If I started while it is too cold, it would freeze after booting into windows (I dont know why). Only way out would be to force shutdown by holding power button.
My workaround was to set a hard disk password. That way I can let it wait for a minute or two, and then type the password. By this time, the lap would be nicely warmed up and I will not experience the freeze.
............Until Laptop broke down and locked HD with it.........
I tried HDPARM through Hirens Boot CD (Parted Magic), and tried to feed the password as HEX (scan codes) as Maximus had suggested. HD did not Unlock. May be Inspiron uses Different scan codes?
And then...Found an Identical Inspiron 1464 through a friend, went over to him, and removed the password through BIOS.
Thank you all for your help. I appreciate it.