Well guys, I feel like an idiot. Here's the situation. I put together a bootable USB with Snow Leopard and Multibeast in an attempt to help a friend Hackintosh his Vaio. When I attempted to boot the Vaio off of the USB, it held a black screen with a blinking cursor in the top left. This made me think that the USB wasn't bootable, after all. To check it, I stuck it in my 2007 MBP 15" and restarted while holding down the option key to bring up a list of bootable drives. The USB showed up on the start screen and, like an idiot, I selected it and hit enter. Big Mistake. The computer then shut down. So I removed the USB and attempted to boot the computer. The computer pulled up the grey apple logo screen, but never chimed. It then promptly shut down again. So I hit the power button again and held down the option key. So up pops my main boot drive and my recovery partition. I selected the recovery partition and the computer once again shut down after briefly showing the Apple logo. Now, the computer does not respond to the power button at all and I'm worried that it's kaput. Please help me!