The Backup Exec Device & Media Service: Service failed to start. (15) Service Logon Failure.
This can be caused by a "corrupt" account.
1. Go to services.msc
2. Locate Backup Exec Device and Media Service.
3. Right Click on the above service and go to properties.
4. Try to use another user with appropriate rights ( local administrator or domain administrator)
Make sure the user is not locked in Active Directory.
5. Apply the correct password for the user account and then save the changes.
Start the Device and Media service.