Although I am Linux user I still have dual boot for my home Computer.
After installing Ubuntu 9.04 I installed Windows XP & lost Grub.
To Rescue Ubuntu I created Ubuntu USB boot. Boot Computer using usb & used following commands to get grub working.
sudo fdisk -l
sudo mount /dev/sda8 /boot (you should know your boot partition)
sudo grub-install /dev/sda
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