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.
Step 1: Getting Prepared
1. A PC running Windows 7, with at least 30 GB of free hard-drive space.
2. A CD/DVD burner and blank CD/ DVD or a USB drive with a capacity of 1GB or more
3. An external Harddrive big enough to backup your Windows installation
4. Administrative access to the PC
5. Internet Connectivity
Most PCs sold in the last three years should meet the criteria for number 1. To confirm what version of Windows you are running, go to My Computer and click on “System properties.” The listed version should be Windows 7.
From that same screen, you should see how much free space you have left, which is underneath the blue bar for each disk. In the example image, there is "8.49 GB free of 55.7GB".
NOTE: The 8.49GB shown in the example is not enough space for most people. While you can install Ubuntu to a partition this size, you will typically want more space store documents and applications. 20GB is probably the minimum size you would want.