Pretty much follow bac's advice, if it doesn't work after drying it, try replacing the battery, and you might get lucky. Sometimes it's the logic board, which really sucks. However, other times it's just a display replacement. What I've seen the most is display+battery, and then logic board is pretty much unfixable (it's not worth the time money or effort). A common problem is the screen is not backlit, which means the logic board is damaged.