I have a ASUS Motherboard system with 2 hard drives. The Primary Drive has WinXP Pro and the secondary drive has WinXP 64 bit. I was able to select the OS at the boot time. Recently I had to rebuild the primary drive OS. After the rebuild, when the dual boot option appears, if I select the second disk with XP 64, I get "Unable to boot error". How do I get the dual boot back again without re-installing the XP64 on the second drive? Any help is appreciated. Alex.