Ok, so what you need to do first of all is burn the LiveCD .iso to a CD, with Imgburn, once you download it. Use the "Write image file to disk" option to ensure it gets burnt successfully as an image. Then, once you got your LiveCD, reboot, and enter the BIOS by pressing the key it tells you to (normally F2, Del, or similar) at the first splash screen you get to after your computer turns off, and then turns back on. Once you're in the BIOS, look around for an option called Boot Sequence, Boot Order, or something to that effect, and put your CD/DVD drive first, so it boots first instead of the HDD. Then insert the CD, save the changes, and exit the BIOS. It should now boot from the LiveCD. Once you get past the point where you select your langauge, you should get to a screen with options like "Try Ubuntu with no changes to my computer", "Install Ubuntu", and other such options. Select the "Try Ubuntu with no changes..." option and once you get to the Ubuntu desktop, navigate tor Places>Computer, and you should be able to see all of your partitions, and browse the contents. Then you can simply copy over the data from your partitions onto external storage, and you're done...unless you want to install Ubuntu of course.