So if I get this correct you have XP there and want to boot it with grub, if you don't have a actual OS installed with grub you can just load the windows bootloader if you havs XP cd. Grub can be setup to run without a os though. To use grub by itself to boot XP is the long way to go there is actually a bootloader called lilo that would do the boot.
The best way for us to see, at least me anyway to see, what you have would be to boot a live ubuntu cd in that virtual set up and download this link extract it to your desktop and run the command. This generates a results.txt, then copy and paste all the text from that to a reply. When you do this open the reply click on the # in the panel of the reply to generate code tags a then paste the text between them.
sudo bash ~/Desktop/bootinfoscript