How to obtain the installation source download and license keys for NetBackup Server, NetBackup Ente...
Which states:
"...
The 6.5 and 6.0 installation source for all NetBackup Server, NetBackup Enterprise Server and components can be obtained via FileConnect.
...
A serial number is required to initiate the software download through FileConnect. This serial number is specific to the FileConnect site and is not the NetBackup license key. The serial number will either come with an upgrade or purchase letter.
If this information is not available, a serial number it can be procured from:
Symantec Licensing Portal:
https://licensing.symantec.com/acctmgmt/index.jsp
or request a FileConnect serial number through Symantec Customer Care:
http://www.symantec.com/enterprise/support/assistance_care.jsp
..."
But,
have you still got your original media-kit? It should be on there.