[chscag]

Well, it's not a firmware issue. If you've properly gone into Control Panel, Sounds, and ran down the list of sounds de-selecting those that you don't want including the Windows Startup, Shutdown, Log On, Log Off sounds, you should not hear it.

Do you by chance have any sound themes selected from running MS Office or any other Windows app that has a sound theme? How about any installed Windows themes? Window Blinds? Theme Changer?. etc?

Check everything. That sound has to be coming from somewhere.

Regards.