How do I keep my Drupal 4.7 site(s) backed up?

There are several modules to help you:

• backup.module Creates an on-demand tarball backup of your database and site files, and downloads them to your browser.
• Database Administration module Allows interactive backup of database tables (among other things.)

Another approach is to build a shell script that dumps your database tables and site files into a gzipped tar file on a regular schedule, and set up a unix/linux cron job. (Or, if you are Windows-bound, and have control of the task scheduler and other appropriate permissions, you can schedule a batch file to do the same thing, asssuming all the necessary command line utilities are available to you on the Windows machine. YMMV.)