15" Macbook Pro, 2007, Intel Core Duo, Snow Leopard. Experienced a major crash, with black blotches appearing on screen. Now won't restart, or boot from install DVD. Safe Mode boot starts with fragmented image on screen, and seizes at "IPv6 pakect filtering initialized, default: to accept, logging disabled". Any ideas? The fact it won't start from DVD makes me think this isn't harddrive related. True?