Recovering Grub on ubuntu using live media(cd/removeable device)
it is very easy to recover your grub when it crashes there are many problems just follow the following steps.
1)Insert your Ubuntu CD, reboot your computer and boot into a live session.
2)Install and run Boot-Repair to reinstall GRUB
if you don’t know about reinstalling grub or Boot-repair so follow this link because i am going to type all that stuff 😀
click here for Boot-repair and recovering Grub 🙂
3)Reboot without the CD. Grub should be installed and both Ubuntu and Windows should have been automatically detected and listed in the menu.