my powerbook g4 will not boot up. i get a blue screen. i have tried to start up in safe mode, but get the same blue screen.

My Powerbook G4 (with Snow Leopard operating system) will not boot up, I get a blue screen. I have tried to start up in safe mode by holding down shift key after startup tone, but end up with same result...blue screen. I need important photos and documents of this laptop, Even if I can just get it started up one more time. Need help fast! If you know what to do, please message back.