ok, my cousin wants me to make him a program. It will run in the system tray. When he double-clicks it, it opens up and asks for a password. When he types in the correct password, it makes a folder (for example, c:\hidden) visible, but then when he double-clicks the icon again, it hides it, so that it's hidden in Explorer, except when "Show All Files" is selected.

I haven't been able to figure out much about system trays, nor about changing folder options...