GRUB2

Anleitung von http://www.howtogeek.com/114884/

Graphical Method – Boot Repair

Boot Repair is a graphical tool that can repair GRUB2 with a single click. This is the ideal solution to boot problems for most users.

If you have the media you installed Ubuntu from, insert it into your computer and restart. If you don’t, download a Ubuntu live CD and burn it to a disc or install it on a USB flash drive. You can also download a dedicated Boot Repair live CD.

After booting into the live Ubuntu environment, open a terminal from the Dash and run the following commands to install Boot Repair:

   sudo add-apt-repository ppa:yannubuntu/boot-repair
   sudo apt-get update
   sudo apt-get install -y boot-repair
   sudo boot-repair