If you are using your LAN for business purposes, you really should have a good backup system to protect your business data and your investment in setup and configuration. As my friend Richard Katz says, “If you don’t back up, you may have to back up a long way.”
If you don’t already have one, install a tape backup unit and, preferably, a good commercial backup software package on at least one main computer on your network. Follow the instructions on the software to configure it to perform automatic backups.