v8.5 was a free upgrade from v8.0 IIRC.
You could always try an uninstall - Program files only, then install the last v8.5 build to the same place. This should keep all your local info (jobs, schedules media sets, job logs, catalogs, etc)
'Course if might not hurt to shut down BEWS and take an NTBackup of the entire\BackupExec install directory