Once something is burned to a regular CD it can NOT be removed. Therefore, you don't have to worry about potentially deleting a file. However, a CDRW is like a floppy disk and files can be deleted.

Windows XP makes it very easy to copy to a CD. In Windows Explorer you simply click on the files you want copied to the CD and select "Copy to CD". A balloon will come up saying "You have files waiting to be written to CD". Click on that balloon and then click "copy". When you want to put more files on the CD, just follow the same steps.

I make additional backups and store them in locations other than my house, such as my parents' house, just in case!