When I attempt to install boot camp on my macbook(I have done it once, before, i deleted it but now i need to install it agian), the attempt to partion my disk fails, and the reason the reason given is that the disk cannot be verified. It says use disk utility to fix this problem. so i go to disk utility and try to verify. It says the disk needs repair. But it has no repair disk option. How to I repair my disk? am just not seeing the button or is much harder?