Mid '07 MB black - Kernel panic, will not boot

I received a hand-me-down macbook. It was working fine one day and the previous owner was trying to connect it to a flat screen tv. It immediately went into a kernel panic. He restarted and before it boots it hits a kernel panic and tells you to restart. Now everytime you boot it says that. I tried replacing the ram and no difference. It's not the RAM. It won't boot in safe mode. I read somewhere that holding d will make it run a hardware test but that doesn't work. Nothing does. What could it be? I have no disks available since it is a hand-me-down. How can I trouble shoot it in my situation?