Hello, I'm using an early 2008 mac pro with plenty of RAM and an 8800GT graphics card. I used Boot Camp to make a partition on the main system drive, put Vista 64 on there. It worked fine, except a lot of the software I need doesn't work in Vista 64. So I put a new drive in there (a WD Raptor) And installed XP 64 on there manually - not using the Boot Camp Assistant, just booting from the CD, selecting the drive, and so on. After getting all the drivers to work, the system ran really well. It was amazing! However, the Vista partition stopped showing up when I option-started the machine. No big deal, however, because I was no longer using it. Yesterday, I used Boot Camp Assistant to remove the older Vista 64 partition. The next time I option-started the machine, the XP 64 partition was gone. I only had the option to start from the OS X system drive. The drive is also not available as a startup disk option in System Preferences. The drive is still in the machine, all the files seem intact. I tried removing the OS X drive, leaving only the XP 64 drive, this left me with zero options when I option-started. Can anyone help me here? What do the option-starting and the System Preferences look for when they're identifying a startup disk, that the XP 64 drive is now missing? Is there simply a file somewhere that I can edit that will add this drive back on the list of bootable devices? I'm at a loss here. Help !!!