well if i got it right u have reinstalled windows xp so your grub bootloader in the MBR is overwritten and you want to recover and reinstall grub .
so for that purpose do
1.insert the fedora 8 dvd or cd whichever is available with you and start with recovery mode.
2.change the root dir by chroot
3.try to find using "find /boot/grub/stage1" this would provide u the path like (hd0,0), use this in next step
4.use the command "root (hd?,?)"
5."setup (hd?)" //use the same hd partition u used above like hd0
6.quit
7.reboot

try it.it all done
if u get any problem do reply