wiki:DualBoot

Notes on installing Ubuntu in a dual-boot configuration

A dual-boot configuration is where you have Windows already installed on your computer, then you create new partitions in free space on your hard drive, then install Ubuntu in those new partitions. Ubuntu installs its own bootloader, called GRUB, which then lets you pick between booting Ubuntu or Windows. So, GRUB has to load before Windows loads. This means GRUB must be installed into the same location on the hard drive where Windows' bootloader was originally. Sometimes, or maybe always, this makes it so right after you install Ubuntu, you can't boot Windows anymore until you restore the Windows bootloader in a new location. Here is how to do that.

  1. Check to see if you have an active entry for Windows in /boot/grub/grub.cfg that points to the first partition of your first hard drive, which should be "(hd0,1)" in GRUB's syntax. If you do, that's good; if you don't, read up here on how to add a line for Windows there. To open that file, type this in your command line once you've booted up Ubuntu:
sudo gedit /boot/grub/grub.cfg
  1. If you already have an entry for Vista in menu.lst, the next thing to try is to use your Vista installation CD to repair your Vista installation. Specifically, you probably need to reinstall Vista's bootloader. Here is how your computer normally loads Vista:

BIOS -> Vista Bootloader -> Vista

Here is how a dual-boot Ubuntu installation loads Vista:

BIOS -> GRUB bootloader -> Vista Bootloader -> Vista

So Ubuntu's installer installs GRUB where Vista's bootloader used to be, and may render the Vista bootloader inoperative as a result, requiring you to reinstall the Vista bootloader (or maybe only repair its configuration).

Here's how to reinstall the Vista bootloader:

http://ubuntuforums.org/showthread.php?t=828862

If you don't have the Vista installation CD that thread gives this link to download a Vista recovery CD that should serve the same purpose.

Last modified 7 years ago Last modified on 06/07/10 11:32:41