Bad news mate. Sounds like your drive is dead.
I know it won't help much so I won't elaborate, but judging by all the elements (symptoms, drive age AND type) it is now heading for a better world.
Where data is inconsistent, permanent... Where Angels compose chiptunes on A500s ;-)
notice that I did'nt put out the "u should backup" phrase. You don't need that now. :-(
pX
