Okay, so I might be completely crazy, BUT: if you could install windows 7 to the usb drive, and then just change the boot.ini file to point to the VHD...it should work... You could always delete the Widnows 7 install off the flashdrive once your done, and just keep the bootloader parts. you would need a boot.ini file from someone who had previously installed windows 7 to a vhd... Again, Just throwing the idea around. Vinny