1.The purpose of this Instructable is to set up your computer to dual-boot Windows 7 and Ubuntu Linux. Dual-booting is a technique which allows a single physical computer to run two or more operating systems (OSes). This is useful for experimenting with new OSes without putting all your eggs in one basket.
2.If you do want to dual-boot, the most important time-honored piece of advice is to install Linux on your system after Windows is already installed. So, if you have an empty hard drive, install Windows first, then Linux. If you already have Windows installed, you’re clear to install Linux.When you install Linux after Windows, the Linux installer knows how to deal with Windows, resize its partition, and set up a boot loader with an option allowing you to choose Windows at boot time.