You should consider making your own CD. It's pretty simple: go to the
Ubuntu website and download the .iso for your computer, then burn as an
image disc (you can right-click from the .iso in Windows to get this
function). Burn to your CD (you will probably need a blank DVD-R), then
restart your machine (you might have to tell it to start from the CD
drive), and then Ubuntu will talk you through the rest.