Server OS Backup

I want to get help on 2 issues;

Number 1

I have one DC running Windows Advanced Server 2000 in the office environment for 40 users. I want to make a GHOST/BACKUP for its OS, so that if there is an issue I can backup the server.

Number 2

I want to add a backup server in the network so that if the DC fails, BACKUP server take it over immediately and carry on running all the services.