How To Install Ubuntu 12.10 On Non-PAE CPU

Here's how to install Ubuntu 12.10 Quantal Quetzal on computers that don't support PAE. The instructions have been tested on the default Ubuntu 12.10 ISO (with Unity), but they should work with any Ubuntu flavour like Lubuntu, Kubuntu, Xubuntu and so on and probably Linux Mint 14 as well.

Using the resulting bootable Ubuntu 12.10 USB stick, it should also be possible to upgrade from Ubuntu 12.04 to 12.10, but I've only tested it on a clean installation.