I have plugged in a new one and it is working perfectly fine (as already mentioned). But wanted to know if there is any way to give life to the old one, or if anyone have encountered similar problem before and found a solution. (Did not want to destroy another one).
When a chip behaves erratically, the only sensible thing is to bin it, to avoid pulling out hair in frustration, trying to debug something that is in reality a hardware failure.
It is unrepairable and if the silicon was studied in a microscope, breaks or semi-breaks would probably be found.
To avoid this in the future, take proper ESD precautions when handling the chips and don't store them in non-conductive material where they have room to slide around. A standard IC-tube where some of the chips are missing, so the rest can slide back and forth (which make some people do exactly that as a subconscious act), can actually generate quite some ESD, if the tubes are not the type made of conductive plastic (or at least with a strip of that each side).
The pink anti-static bags can actually generate a (small) amount of static electricity, if components are shaken around inside them and they're the least dissipative of all the antistatic materials - mostly good for bleeding off accumulated charges that may happen in "free air". Next up is the static dissipative types and best is the direct conductive types (like the black bags some components are delivered in - save any you get for storing chips and MOSFETs)