I have a family desktop computer which is running Ubuntu 10.04.0 and I am looking to carve out a partition (~10GB +/-) to install 12.04 onto. Version 10.04 will sit in its partition only as a fallback in case 12.04 doesn't work. In the future then I'll use 12.04 and install an update version over the 10.04 partition.

Anyway, since this is my family computer I don't want there to be a long down-time. I thought if I get answers/advice here then if the poop hits the fan, I'll be able to recover without starting to research from scratch.

  1. So if in installing 12.04, something goes wrong and the computer won't boot up, how would I fix the Grub and MBR to use the old 10.04 again?
  2. Once 12.04 is set up (users to their /home directory, programs installed, etc.) I want to set Grub to not show (preferred) or only show for 0 seconds before immediately booting the 12.04 version.
  3. Ubuntu 10.04 is 32bit and I am putting 64bit Ubuntu 12.04. Will this difference cause any problems?

Like I said, I am hoping to gather what to do if things go wrong to quickly revert me back to where I was previously. I already know to backup all of my /home files (which is on a separate partition) and plan on not installing all of the programs I installed previously when I was "trying" them, or thought I would do something with it and never did.

Normally I don't worry about this with my laptop because if it breaks I am the only one messed up but this is the family one and they (at least my son) may string me up if I break it


I'm also interested if you have tried anything similar, and your experiences. I usually don't have problems with Ubuntu so I am hopeful that this will go just as smoothly as the previous times.