I have Windows 7 and Ubuntu installed. When rebooting I always have to choose between those 2.How can i make Ubuntu become the first option when i boot my computer?
Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command below.
gksu gedit /etc/default/grub
Find this line:
0 is now set for Windows 7, change it to the number associated with Ubuntu
Another way is to use Grub Customizer. If you don't have it you can install it:
sudo add-apt-repository ppa:danielrichter2007/grub-customizer sudo apt-get update sudo apt-get install grub-customizer
Whereas the use of EasyBCD to edit the Windows boot loader, may well be a feasible answer when the traditional BIOS and MBR approach to starting up your PC is in use. When the computer in use has been shipped with UFEI firmware and boot manger, as is increasingly the case, then using EasyBCD is (by their own admission) not really appropriate.
One of the alternatives offered (by EasyBCD) is to use a virtual machine. That taken together with another alternative given, which involves Grub2 EFI wresting control from MS UEFI, booting Linux first and ultimately chainloading NTLDR to boot into windows, I’m inclined to get overwhelmed by the unnecessary complexity of it all and say “how do I now make this computer entirely Ubuntu”.
For what you are asking (Windows for the Default), I'll assume that you are using Wubi.
To edit the Windows Bootloader, install EasyBCD. It is a free tool (you'll have to click the "Register" Link at the bottom, although you don't need to register) that allows you to modify the Windows BootLoader in a pain-free way.
Next, launch EasyBCD. Then go to the Edit Boot Menu part, click on the Yes tickbox beside Ubuntu, then click on Save Settings. You are Done!