So my 2003 iBook won't start. When I try to start it, the Apple pops up like a normal start-up, and the spinning thing spins like normal, but then keeps spinning. After a couple minutes of spinning, the computer just turn off. Yikes. I've tried it about 10 times with no luck. Any ideas? I've heard about holding down various buttons on start-up but I don't know what any of them do. Thanks. p.s. I've never had any problems with it until now.