The iWorld

You can disable all Balloon Tips, pop-up reminders coming up in Windows XP system tray :

Click on Start and then on Run.
In the open box type regedit and then click OK.
Go to HKEY_CURRENT_USER / Software / Microsoft / Windows / CurrentVersion / Explorer / Advanced

Create a new DWORD Value with name "EnableBalloonTips".
Set the value of this new DWORD to 0 and base as Hexadecimal.
Save the changes in the Registry and reboot the computer normally.

Congratulations! All your annoying balloon tips of your windows xp system tray have been disabled!