Windows Server 2003 comes witha pre-installed firewall. A firewall is software application or a device that permits or denies traffic to your server based on pre-configured rules. Make sure that your Windows server has the firewall software enabled and that the rules are appropriate to your applications

Run AntiVirus Software

Antivirus software detects and neutralizes malicious software (viruses, worms, trojans) that attempt to infect your server. It is essential to the security of Windows servers and should be installed and running at all times. A comprehensive list of antifirus software can be found at: http://en.wikipedia.org/wiki/List_of_antivirus_software

Backup Regulararly

Backups should be conducted regularly, preferably daily, and stored on a separate location such as Codero.com's Smart Backup service. This not only protects against data loss but it provides options when data integrity is compromised (e.g. a mistyped database command).

Keep Windows Up to Date

Microsoft releases important security and stability updates on the second tuesday of every month. Visit http://www.update.microsoft.com/windowsupdate/v6/ montly to keep Windows up to date, or configure Windows to update automatically using the Windows Control Panel.

Keep Applications Up to Date

Dont forget to check for updates to other software installed on your dedicated server. These can be found at the software vendors' Website and should be included in your regular patch/update schedule.