I have an old MacBook (2009) & it now won't boot up. It shuts off before login is complete. I've tried everything I can think of. I need to recover my data & I foolishly don't have it backed up. (I know, I know…idiot) I've tried repairing it in disk utility but it fails every time. I've tried reinstalling El Capitan but i get an error message every time. So, I just went out & got a new external hd, thinking I could back it up from disk utility but that, too, fails. Please help!