Need Help Please !

Hi everyone !

I have iphone 3gs with problem white screen. when i power up and it come to menu like usual you turn on but when i click on power then is turn the white screen and i trying to hold the power and home button to reset it , i see the logo apple but after that i see the white screen . so anyone know how to fix it or why it cause that problem please help me out .thank you ...

vin