Windows

Whether you have a OEM edition of Windows installed on your computer and you don't have an install disk, or you have finally gotten your Gentoo system up and running, it's a good idea to make a complete backup of your operating system. Although you can generally simply copy the files that make up Linux over onto a different hard drive or partition, with Windows you need to make an image. Making an image also has benefits on Linux, not the least of which is it contains the entire operating system backup in a single, compressed file.

Recently I was working with someone who suspected that their laptop had a virus, and so wanted to do a virus scan. Needless to say, I recommended to them a couple of freely available virus scanners for Windows, but I also recommended that they boot up a LiveCD and run a virus scan from there. Being able to run off a LiveCD for a virus scan ensures that no techniques that the virus can employ on the host operating system to hide itself (such as a rootkit might do) will work.