Hi everyone. The MacBook of someone I know is messing up, and I was wondering if you guys had any advice. I can't get it to work for the life of me. As a side note, this is a professor in a school where I'm trying to get in for a PhD, so fixing this would really help for making people here like me , so a big thank you in advance for any help! Here's what's happening: When I just start it up normally, the apple symbol appears on the grey screen, and then is replaced by the no or prohibition symbol (circle with a diagonal line through it), and it's stuck there. When I try to start it up as an external HD using my computer, it shows up in my sidebar, but cant find anything on it (just has the little spinning symbol for looking). I tried to start it up from a CD to reinstall the OS. It let me go to the screen to choose what Im starting from, but when I choose the CD and tried to start it the apple symbol came and then was replaced by the "no" symbol again, just like when I tried to start it from the hard drive. The fact that it still won't start up from the CD makes me think it is hardware related, since the only things that should be involved are the CD - which is ok, and the hardware. It shouldn't be touching the OS or anything that's already on there. Though I'm not sure if that's correct or not. I tried starting it in the verbose mode, and here is the info it gave me: Loading kernel cache file System\Library\Caches\com.apple.kernelcaches\kernelcache.AF0F1996 . . . Read error 0x7 Loading mach_kernel . . . . Error loading kernel mach_kernel (0x12) Stayed there for awhile and then eventually went to the grey Apple symbol then "no" symbol problem again. Does anyone have any ideas on what to do or how to fix this? Thank you for any help.