The quick answer is that, by default, BackupExec creates a database backup every morning at 0400, called BEDB.BAK. You can use BEUTIL to restore the database from that
For a little more detail take a look at http://seer.entsupport.symantec.com/docs/319367.htm
The title is "How to move Backup Exec for Windows Servers", but includes all the bits and pieces you need, spelled out