I'm having problems with my Ibook G4

I'm having problems with my Ibook G4, I leave it in the car on a sunny day and he ended up overheating after I called and he started off alone. Soon after he turned over, and when I press the power button, it makes a strange noise, the fan rotates at high speed, but nothing appears on the screen, it would be any problem on the memory card? Can anyone help me? Thanks