Knoppix is linux that runs off a disc! it's really cool, nobody should be witout it, it's very handy. It's free/legal cause it's linux, and it doesn't use your HD for anything (at least, it doesn't leave anything on your HD)! It's extremely cool and everyone should get it. go here http://www.knoppix.com/ and click on downloads, then select a mirror and get "KNOPPIX_V3.6-2004-08-16-EN.iso" ! All you have to do once you burn it is reboot your computer with the disc in the drive (and make sure you have your CD drive before your Hard Drive in your boot sequence).