Re: Macbook Pro won't startup
Hold down CMD + S when starting, it'll take you to a black screen
Type "fsck -fy" without the quotes to check and repair your file system. If it finishes with anything other than something like "everything is ok!" then run it again. E.g. if it says "**File system was modified**" then just run the command again.
"As a result of all this hardship, dirt, thirst, and wombats, you would expect Australians to be a sour lot. Instead, they are genial, jolly, cheerful, and always willing to share a kind word with a stranger, unless they are an American." -- Douglas Adams