My PSP Doesn't work anymore, even with charger.

So, I haven't played with my PSP in over a year because my charger was dropped in water, so I got enough money to buy a new charger recently and when I plugged it in, it didn't light up. So I went to gamestop to return the charger when I got the idea that I might need a new battery, so I asked if I could try a battery that the guy at the store had in a working display model. The battery didn't work in my PSP but it worked in his. He said my PSP is dead, and I was wondering if there was any way to fix that?

Thanks in advance for your help!