I followed the instructions to install Windows XP on my MacBook. I had 3 partitions and Windows installer complained about not being able to install because of this. So I decided to follow the instructions and re-initialize my hard drive to 2 partitions. After doing so with Disk Utility, OS X will not install on any hard drive. When the disks to install show up, they all have an X on them and it warns that "You cannot install Mac OS X on this volume. Mac OS X cannot start from this volume". This happens on external firewire disks as well, it wont let me install on any of them (I have reformatted the drive to 1 partition and the problem persists). Any ideas on what I could do to get things back to normal? I am trying to think what could have happened when I reformatted the drive. Maybe the EFI partition was erased and then I am REALLY screwed up. Any hints/pointers that might help me with this would be greatly appreciated. Thanks!