Do you need to hide a program running in the background that shows in your System Tray? Try this reg hack to hide all tray icons. It’s not anything like the Windows XP tray icon hider, this one shows no trace of any icons. It would look like someone closed all background programs.
1) Click on START>RUN and type "regedit" (without the quotes).
Navigate to the following key;
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Policies/Explorer
2) Add a "REG_DWORD" entry entitled "NoTrayItemsDisplay". Open it up and assign the Hex value of 1 to hide the Icons. The value of 0 is normal (default), showing the icons.
3) Close "regedit" and reboot computer and the icons should not be there anymore. Control Alt and Delete will bring up Windows Task Manager and items can be displayed and closed (if need be) from in there instead.
This for restoring it back :
write the following code in notepad and save it such as "edit.reg" without the quotes and run it.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
"NoTrayItemsDisplay"=dword:00000000
after that go to taskmanager by alt+ctrl+delete to processess and terminate the explorer process and go to file start new process and write "explorer.exe" with out the quotes.
see the changes