How to reinstall Grub after burg
Solution 1:
Burg Manager is an application to easily install Burg (along with the default Burg themes and a Burg emulator) and change most of the Burg settings such as the timeout, download and install new themes, remove Burg and restore Grub 2, set the default operating system and many advanced options.
you can get it from here
Solution 2:
To restore GRUB, I think you have to type this into the terminal:
sudo grub-install /dev/sda
Where /dev/sda is your hard drive.