grub change default option

sudo nano /etc/default/grub

the line

GRUB_DEFAULT=0

must be changed with the desired value, indexing starts with 0. Then save, exit and execute:

sudo update-grub

reboot to test...

triple boot 2x Ubuntu and Windows?

https://askubuntu.com/questions/228890/how-can-i-triple-boot-xubuntu-ubuntu-and-windows

Start your installation using the Ubuntu 12.04 LTS CD.

• When you reach the Installation Type Page, select Something Else.
• Now, you will get a page listing your partitions.
• Select /dev/sda2 and select Modify
• Now, give the Use as as ext4 and mount point as /
• You can just reuse your existing swap partition.
• Continue with the installation.

After the installation, you should be having a system that you desired.