OSX won't boot

[gohome190]

Hi
I have an 08 MBP that is boot camped with windows vista. I am writing this on it, using the windows partition. However, I can no longer go into OSX. Whenever it tries to, it has a loading bar for awhile, then stays at the apple logo. It'll then stay there forever! What can I do?

Thanks in advance!

 

[calderone]

Hold Command + V when you turn the Mac on. This will put it into verbose mode. This will allow you to see what is stopping it from booting.

 

[gohome190]

it says drive MACINTOSH is unable to be repaired. uh oh. now what?