Ok, So I have a bit of a unique situation here I could use some help on.
I've modded my summer 2011 MBPro to have 2 harddrives by replacing the optical drive. OSX Mountain Lion is installed on a single partition of a 120GB SSD. The second drive is 750GB, partitioned as 550GB, 150GB, and ~50GB. I've set the 550GB to act as my OSX homefolder, but I'd like to install windows 7 and Windows 8 on the remaining partitions. It Took a while, but by following this guide, I eventually found a way to install Windows without a CD/DVD drive by following this http://huguesval.com/blog/2012/02/installing-windows-7-on-a-mac-without-superdrive-with-virtualbox/
It worked flawlessly for creating both windows 7 and windows 8 images that I could clone onto FAT32 partitions. However, I have encountered a problem when trying to triple boot. After I put Windows 8 onto the ~50GB partition and tried to boot into windows 7 I get an error that says something like:
error: 0x0000000e The Boot selection failed because the required device is inaccessible.
If I re-clone the windows 7 image onto the drive and select the option to "replace BCD" file for the drive, windows 7 will boot but windows 8 now gives me the same exact error.
I realize this is a pretty extensive setup, but if anyone has some insight I'd love to hear it.
Edit: I've tried installing windows from a USB, but my firmware doesn't let me. I get an error "No boot device detected". I get the same error when trying to use an external CD/DVD drive. As far as I know, only the recent 2012 Retina Macbook Pros and Macbook Airs are able to install windows via USB.