Boot into a live CD (or live USB), mount some systems, chroot into it and install the kernel. After a successful installation of the kernel, unmount the filesystems.
- Open Terminal
- Mount the Ubuntu partition: sudo mount /dev/sdXY /mnt
- Mount some special partitions:
sudo mount --bind /dev /mnt/dev sudo mount --bind /proc /mnt/proc sudo mount --bind /sys /mnt/sys - Chroot into the /mnt: sudo chroot /mnt
- Install the Linux kernel: apt-get install linux-image-generic (no sudo required as you are root after a chroot)
- After a successful installation of the kernel, get out the chroot and unmount some filesystems:
exit sudo umount /mnt/sys sudo umount /mnt/proc sudo umount /mnt/dev sudo umount /mnt - Reboot and remove CD or USB: sudo reboot
Please note: if the kernel you've install doesn't show up press "e" and change the kernel name for example: to 2.3.0-25 and it should boot.
Next step download Boot Repair
sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair
sudo apt-get install -y boot-repair && boot-repair