Using Knoppix Linux Live CD to Rescue Windows
Sometimes a Windows installation will become unbootable. You might turn on your computer one day and see nothing but a mostly blank screen with a confusing error message.
When this happens your files are usually still on the hard drive, but you just can't boot into Windows. The Knoppix live CD is a great solution to this problem becuase it allows you to boot up your computer from a CD and have access to all of your files even if Windows won't boot.
Once you have booted the computer into Knoppix, you can copy the data on your Windows hard drive onto an external storage device like a USB thumb drive or external hard drive, or even a digital camera. (See the note at the bottom of this post.)
Tom's Hardware has a good article on booting up a Knoppix live CD on your Windows computer. The article demonstrates an older version of Knoppix — 3.3 (currently at version 5) — but the explanations in the article are still useful. The author also writes about using Knoppix to save a damaged Windows installation.
Note: with Linux live CDs you can safely read your files on your Windows hard drive. Do not write to your hard drive if it is a Windows NTFS-formatted drive (Windows XP default). The Tom's Hardware article talks about NTFS-write support, which does come with Knoppix now, but it is not 100% reliable. With Linux you should generally only write to drives that are formatted as FAT32, or in a Linux file format. You can use Knoppix to format an external drive in a supported format. You can use Knoppix to shrink NTFS partitions to make room for a Linux formatted partition (defragment the NTFS drive first). You can also safely write your files to CDs and DVDs using the included K3b CD-burning program. If you are going to attempt a Windows-rescue with a Knoppix CD search Google for detailed instructions first, or ask in the forums here on this site if you have any questions.