The following tip will help you to disable balloon tips in the notification area. To achieve this follow these steps:
Click Start, click Run, type regedit, and then press ENTER.
Locate the following subkey:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
Right-click the right side pane, create a new DWORD value, and then name it EnableBalloonTips.
Double-click EnableBalloonTips, and then give it a value of 0.
Close Registry Editor.
Log off Windows, and then log back on.
Balloon tips should be off now.
You can also use an app from Microsoft which will do it automatically for you:
http://download.microsoft.com/download/8/8/6/88649061-8A6C-4045-927B-0154A075635E/DisableNotificationBalloonTipsInWindows.msi