How to mute bootup sound? Possible Duplicate:
  How do I disable or get rid of the startup sound my Mac makes?  




I have an old MacBook Pro (pre-unibody) running OS 10.6. I am annoyed by the traditional Macintosh bootup sound, which I want to mute permanently.

I've tried some proposed solutions:


Remembering to reduce the volume before I shut the computer down. It works, but it's not reasonable to do this.
Pressing the "Mute" button while booting up the computer. Seems to be the F3 key on my old MacBook, but that doesn't work.
Installing and using the application StartupSound. It didn't work. I read in forums that other users share this problem.


Am I doing something wrong, or is there another solution to my problem?
StartupSound works for me. It's true that it is sometimes not totally OK, but if you set different sounds volume, or check-unchech the mute radio button, finally it does the job.