HP BL680c - ProLiant - G5 Getting Started Manual page 6

Enabling entitlements
To obtain and install the software and licenses for Essentials for XenServer, HP
Platinum Edition, and HP Enterprise Edition follow the instructions on your license
entitlement certificate.
Recovering from a system failure
If you encounter a system failure and need to reinstall, see Installing Citrix XenServer
from HP.
IMPORTANT: Using the Install CD completely erases all existing
data and user configurations. All preconfigured settings and user
data are lost.
IMPORTANT: If you are performing a system recovery and your
previous installation included a Citrix Enterprise license or an HP
PVC license, you must reapply the licenses to enable the same
level of services you had with the previous installation. If you no
longer have the Citrix Enterprise license or the HP PVC license,
you must obtain a replacement copy through the HP website
(http://www.webware.hp.com,) or by contacting the HP License
Center using the contact information located on the Entitlement
Certificate.