Ghost 9 doesn't recognize drive

I just installed Windows 7, but before doing so, I backed up my hard drive with Ghost 9 (as I have been doing for the last few years).  I now want to return to my XP install, but Ghost doesn't recognize the hard drive when I boot off the CD into the recovery environment.  It recognizes an external USB hard drive with the image, but not the one where I want to install the image.