You use the Cluster Configuration Wizard to remove Backup Exec.
To uninstall Backup Exec from a cluster
From the Tools menu, point to Wizards, and then click Cluster Configuration Wizard.
Use the wizard to remove cluster-aware Backup Exec from all selected servers.
When unclustering the active node, you can either leave the Backup Exec data on the shared drive or delete it. If you delete the data, you can make the data available on the active node.
After Backup Exec has been uninstalled, move any resource disks from the Backup Exec cluster group to another group, and then delete the Backup Exec cluster group.
On any node, click Start, point to Settings, and then click Control Panel to uninstall Backup Exec.
Double-click Add/Remove Programs, and then in the list of currently installed programs, select Symantec Backup Exec for Windows Servers and click Change/Remove.