A while ago my mid 2009 macbook pro crashed when the battery died. It has done this before and restarted normally when the battery was charged, however, this time it did not. I try to start the machine and I just get a grey screen with the apple logo, a swirling icon, and oddly, a blank loading bar (kind of). That has never appeared before. If I let the computer try to start, the bar goes away, but it never boots. I have tried booting from my instillation disk, which is the newer Snow Leopard disk. It won't recognize it. I put it in the drive and press c, nothing works. I tried holding option. I have cleared the pram and nvram, I have tried starting in safe mode. If I could just make it boot from the Snow Leopard disk I would just wipe it and do a clean install, because I have an external hard drive with everything I have backed up on it. I'm not worried about losing data, I just want to wipe the hard drive and have my computer work. If I run it in control + shift + v, it tries to start up, goes through some processes, and tells me that the volume macintosh HD cannot be repaired. What can I do? I can't get my laptop to boot from the Snow Leopard disk. Is there any other way to wipe or fix the hard drive so I can reinstall?