You can download a complete version of Ubuntu Linux from the Ubuntu website. The ISO (or CD) image is around 700MB. Two versions of Ubuntu are supported: 6.06 and 7.04 - we're using 7.04 for this walkthrough. To follow suit, select Desktop Edition, Ubuntu 7.04.
Select a local source for the download, as this may speed up the transfer rate. Save the downloaded image somewhere on your hard drive rather than running the file immediately. This way, if you want to install Ubuntu on a second computer, you won't waste time downloading the file again.
Create a CD containing the downloaded image file. Although some computers are able to boot up from a CD image stored on a hard drive, more are able do so from a disc. Using CD-burning software, such as Nero Express, select the Disk Image option and browse to the file you saved in step 2. Click Next.