i am not sure about the first question but the most icons that appear in the system tray are found here: start->run->msinfo32->startup tab.
you could deselect the items you do not want to load. The list is made up from the registry
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ RunServices
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ RunServicesOnce
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ RunOnce\Setup
Good luck
noODle ::http://doscerveza.ontheweb.nl (in construction)