Since I've started using Ubuntu again, I got my 32 bit installation running great and everything configured how I wanted it. Then I realized I could use 64 bit, never occurred to me before. Well I happened to have left half my hard drive unpartitioned incase I wanted another OS to dual boot with, so I went ahead and downloaded 64 bit Ubuntu and installed it on my free space. The problem was that the bootmanager (GRUB) was installed on my first partition, and it wasnt getting updated with the new ubuntu installation. Heres how I fixed the problem.
First, open a terminal on your first installation of Ubuntu, and type
$ sudo gedit /boot/grub/menu.lst
scroll down to the bottom and you should see a section that looks somewhat like this
Its simple enough, just add another entry to the bootloader. So first get your second install finished then come back here to do add it in.
Take the first entry in there, where it says "title ubuntu 7.10, Kernel 2.6.22-14-generic" and copy that whole section, and paste it in there again. (Im gonna pretend you pasted it at the bottom). First you should change the name to something you'll recognize so you dont get confused over which partition is which. Change the part after the word "title", I called mine "Ubuntu 64 bit"
Next you have to tell it where the "root" is on the hardrive. You'll see it probably says "(hd0,0)" (like mine does, for this the numbering starts at 0, so 0=1 and 1=2 and 2=3 and so on..). That tells the bootloader that its on hardrive 1, partition 1. My swap partition is next, so thats (hd0,1), now my third partition is where i installed my 64 bit ubuntu. so I would tell it "(hd0,2)", name yours accordingly to how you installed it.
Now tell it what your kernel is, if you installed a different distro of linux (like dreamlinux, or a different version of ubuntu) then you will want to make sure you get the right file. Open your
(new partition)/boot/ folder and find the kernel file, type its name in exactly as you see it. to get your UUID just right click your hardrive (You can find it by opening your
My Computer Folder), select
Properties and go the the
Volumes
tab at the top. write in your UUID exactly as you see it on that window. After UUID write in "ro quiet splash" (on the same line as the end of your UUID).
Now find your initrd file in the
(new partition)/boot/ folder and type its name in exactly as it shows there, except for the .bak at the end of it. Thats not supposed to be included. Now hit the enter key and on the last line all by itself type "quiet" (without the quotes of course).
That should do it, just save and close the file and then you can reboot and find your new install using hte Grub menu. Its worth saying, whichever boot entry is on top (right below the line that says "## ## End Default Options ##") is going to be booted by default.
