So, last night I found that my Macbook Pro (Late 2007, Santa Rosa) wouldn't output to the screen or an external. I thought I had the dreaded video chipset failure that Apple reported more common for my model. However, when I started up today, after leaving the battery out for awhile, the screen started working again... but Mac OS X did not. I'm currently stuck at the Apple logo with the spinning loading thing. I've left it on for over 3 hours and it still stayed there. The laptop gets hot and the fans spin up to ludicrous speed. When I hold option down at boot, it shows my Windows partition and my Mac OS X partition, but instead, it's called "EFI Boot." Did my Mac OS X get corrupted somehow? Should I backup the contents of my drive and reinstall Snow Leopard? I've tried resetting my PRAM, inserting the Snow Leopard DVD and booting holding C, tried booting holding CMD+S to get to the terminal screen. It just ignores it all and goes tot he Apple screen, starts a grey progress bar, then sticks on the swirly loading icon infinitely. I'd appreciate suggestions. Thanks for the help!