Several tips registry was supervised this only for Windows XP. Before edit the registry, good for you to backup before

1. Click the Start Button > Run
2. Type regedit and press Enter
3. In Registry Editor, choose File menu > export
4. After export registry file, save them.

Warn! Editing your registry editor could crash your Systems Operation, so always backup your original Registry.

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Curr entVersion\Policies\Explorer
Make a new  DWORD Value and rename to NoTrayItemsDisplay.

Double click NoTrayItemsDisplay and insert Value Data 1.
To restore System Tray, insert 0 on Value Data.