Usually users have only one operating systems installed on their home computer. Most popular is Windows. But there are also a big number of Mac users and of course, a nice handful of Linux users. But there are users that want to use multiple OS-s on their machine. For that, multiple solutions can be used like VMs, live disks or dual boot.
Usually, dual-boot system is a computer that runs an Windows Platform and a Linux distribution at the same time. Both of the operating systems are installed on different locations of the hard drive and when computer starts, a menu is shown with possibility to choose which OS you want to boot (to access).
In my case I have Windows 8 and Ubuntu 14 on my laptop. And there is GNU Grub, a so called boot loader, that helps me to choose between Ubuntu and Windows when I start my laptop. Grup is set my default to access Ubuntu. If i don’t make any selection for 30 seconds, my laptop will boot using Ubuntu.
The problem is that, I am more like a Windows user. I just use Ubuntu for some very special projects and most of the time I need to boot into my Windows. Therefore, is better when the default boot option is Windows and not Ubuntu.
If you run into the same problems then the next steps will help you to change the default boot option from Ubuntu to Windows 8 (or 7 or even earlier).
1. Open terminal and type
grep menuentry /boot/grub/grub.cfg
2. Type in the terminal sudo nano -B /etc/default/grub and your admin password. The nano editor will open.
3. Change GRUB_DEFAULT=saved and add GRUB_SAVEDEFAULT=true
4. Save file by pressing ctrl+o then enter and close it by pressing ctrl+x. Update Grub setting by typing sudo update-grub into terminal.
5. Exit terminal and restart PC. After you choose Windows, Grub will select it as default.
Enjoy!
via [askubuntu]