I recently got a new machine at work and it has Windows 7 on it. The problem is the little red dot with a cross saying that "no speakers or headphones are plugged". I know it's so, as I didn't plug any. And I wouldn't. Is there a way to disable this warning?
It is really simple. You either have no speakers or headphones plugged in which is indicated by the icon... or you do. This really isn't a warning, but rather a status update. You could hide the icon if it bothers you that much.
Start by right clicking the "up-arrow" on the tray icon container thingie:
And go to properties. From there, switch the "Volume" to "Off":
Hit "Ok" and after that, you will no longer have the volume icon. You can reverse the process to re-enable it.