Stemming from comments in that article, and email from readers, I decided to revisit that tutorial using Ubuntu 12.04. So the purpose of this article, is to show how to dual-boot Windows 7 and Ubuntu 12.04 on a computer with one hard drive. And it will be on a computer with an existing installation of Windows 7. If there is a need to, you may reinstall you copy of Windows 7.
First things first. Download a copy of Ubuntu 12.04 installation image from here. Depending on your platform, you may download the 32- or 64-bit installation image. Images used for this tutorial were taken from test installations using a 32-bit installation image in both a virtual environment using VirtualBox, and on real hardware. In either case, I did not encounter any errors that others have reported, so I am certain that if you follow this guide, you should have a computer with both Windows 7 and Ubuntu 12.04 installed in a dual-boot configuration.