You should note that this will disable all balloon notifications, so proceed with caution.

Click on Start \ Run and type in regedit

Now we will navigate to this path in your registry.

   

On the right pane right click on an open area and choose New \ DWORD Value  

You will see New Value #1.  Change this to EnableBalloonTips.

Next double click the new registry entry you created.  In the Value Data field set it to 0 (zero).  Make sure Hexadecimal is selected under Base.  Click OK.

Finally restart your system and enjoy the clean boot up with no balloons popping up at you.

To remove this registry hack, just delete the registry key that you created.