Having a backup is always important
For files I use Second Copy(to clone all my personal files to a external drive), it works well(but does not retain creation dates from the original files
For a windows drive image, something like this may work for you. I have used it to migrate from one drive to another. Since it creates images, you can actually reach into the images and grab a file should it go corrupt. They list a recovery CD/DVD as well(that I have not tried, but should allow you to restore an image even if windows has failed to load)http://www.todo-backup.com/products/home/free-backup-software.htm
These are not ISO files but are image files.