It is absolutely essential to back up all data files, and a compact disk is the most versatile and cost effective way of doing this.
I've have also found that by having more than one hard disk, or several partitions, it is also easy to back up the Windows operating system using Norton Ghost 2003. The best way is to only have the basic Windows installation on drive C: and put everything else into partitions. For example:- D: for applications, E: for general data, F: for Photos, and G: for Internet files, G: for CD-writing. Partition Magic is the best program for doing this.
You can then easily create an image file of any partition (which creates a .GHO file, compressed in size if you want). This backup file must be stored elsewhere than on the drive being imaged, so you will need plenty of spare hard disk space, a tape backup system or means of writing the file to several Cd's.
Should (sorry, when) Windows goes pear shaped, you can recover drive C: from the DOS prompt (or with Windows XP the Ghost boot up floppy disk). This can take as little as 5 mins, or 15 mins for a large system, and everything is restored back to normal, and it works every time. Of course it will back up and restore any other partition too.
Using Ghost Explorer it is also possible to recover any file or directory using an explorer type window within Windows.