You can disable/enable the balloon notifications in the notification
area next to the clock.Navigate along the path below :


- HKEY_CURRENT_USER
\Software\Microsoft\Windows
\CurrentVersion\Explorer\Advanced\


In the right pane select the entry :

EnableBalloonTips

(Set it's value to 0 to disable it and to 1 to enable it.)


If the entry is not there you need to create it.
(Right click in right pane , new , REG_DWORD [Dword Value])
Name it : EnableBalloonTips

This needs a restart!