If you want to disable the System Tray on Vista / XP try this simple registry hack
Note:- Before doing any changes to registry take a complete backup of your registry
open registry editor frpm start—>run type regedit click ok
Navigate down to the following key from the left pane (if it doesn’t exist Create )
Create a new 32-bit DWORD value in the right hand pane with these values:
You will have to logoff and back on for this to take effect. To remove the hack, just delete the key, or change the value to 0.
Note that disabling the system tray doesn’t actually prevent system tray apps from running, it just hides them.