This is from support.microsoft...
To disable balloon tips in the notification area, follow these steps:
1.Click Start, click Run, type regedit, and then press ENTER.
2.Locate the following subkey:
HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre ntVersion\Explorer\Advanced3.Right-click the right side pane, create a new DWORD value, and then name it EnableBalloonTips.
4.Double-click EnableBalloonTips, and then give it a value of 0.
5.Close Registry Editor.
6.Log off Windows, and then log back on.
Obviously, 'EnableBalloonTips' is recognized by the operating system. But why doesn't it already appear in the listing of registry variables?