How retrieve your grub after windowsxp install :]

a) Strated the Ubuntu Live CD
b) Open a terminal and put the commands:

$ sudo grub
grub> find /boot/grub/stage2

We will show a parameter (hdx, y) for mi is: (hd0, 6)

grub> root (hd0,6)
grub> setup (hd0)
grub> quit

and that's all.