Sasa - No, I'm afraid I don't know. It could be anything from static electricity having shorted something out, to that gold prong I described above not making contact anymore. It's even possible you had it in your pocket with a thumbtack or a metal shaving from something having rubbed off, and it got stuck. Mine was doing it when I bought it, so I haven't a clue. I just know that $20 in parts and an afternoon in work and I got it all working.
What kind of water damage? Do you know what happened? Have you tried charging it from a wall charger and a computer?
Cheers.