Learn how to upgrade
You can upgrade from the Evaluation version of Windows® Home Server to the fully licensed version. Boot your home server from the fully licensed Windows Home Server DVD, and then select Server Reinstallation. When prompted during Setup, use the product key from the fully licensed Windows Home Server DVD.
All of your Windows Home Server shared folders and computer backups are preserved during an upgrade. However, you need to recreate your user accounts, reinstall any installed applications, and reset your Windows Home Server Settings.
As an added precaution, make sure you copy all of your important files located in your shared folders before you begin the upgrade.