My wife just tried installing Snow leopard but right towards the end of installation it said an error occured and it just kept "thinking". I eventually just had to turn the power off b/c it was "thinking" for 1/2 hour. When I turned the power back on, it just gave me a ? on a folder. I then held the option button and it came up with a screen to install snow leopard again. It didn't work before, so I assume it's not going to work again. How can I make it get off this installer screen and to go back to the regular operating system that is actually installed, not snow leopard. It gives me Utility option on the top, but I don't want to lose important files that were up during the install.