Microsoft officially ended extended support for all editions of Windows Server 2003 on July 14, 2015 Security Risk:

Disclaimer: Ensure you possess a valid license key for legal usage. Using the software without a license is illegal. Security Considerations (Crucial)

Released in April 2003, was a pivotal milestone in Microsoft’s server operating system history. It succeeded Windows 2000 Server and set the stage for the modern enterprise environments we see today. Even decades later, tech enthusiasts, legacy system administrators, and hobbyists often search for the Windows Server 2003 Enterprise Edition ISO to revive old hardware or study the evolution of Active Directory.

Improved Group Policy Management Console (GPMC) and DNS performance.

Choose between "Per Server" or "Per Device/Per User" licensing. "Per Server" is typical for a single server environment. Consult Microsoft's licensing documentation for your specific scenario.

Windows Server 2003 as a Workstation: Great, But Not Unconditionally

Released in April 2003, Windows Server 2003 was a milestone in Microsoft’s server operating system lineup. Built on the Windows XP codebase, it introduced significant improvements in security, performance, and scalability over its predecessor, Windows 2000 Server.

Choose IDE or BusLogic/LSI Logic SCSI . Modern SATA/AHCI and NVMe controllers will result in a Blue Screen of Death (BSOD) during setup because the ISO lacks the required drivers.

Supported up to 8 processors simultaneously.