My Canon S5 IS won't turn on...?

I got it as a birthday present, used, in Feb. It was working fine until my Dad dropped it. Well, he worked on it and got it working again. Then my camera started showing the green screen that eventually faded to white. I took out my memory card and both my external and internal batteries, and it started working once again. I left it at my Nana's for about 2weeks and I'm not sure if it has been throw around or anything but I charged the batteries and it still won't turn on. Help...?